Physics Letters B 721 (2013) 32–50

Contents lists available at SciVerse ScienceDirect

Physics Letters B www.elsevier.com/locate/physletb

Search for displaced muonic lepton jets from light Higgs boson decay in proton–proton collisions at s = 7 TeV with the ATLAS detector .ATLAS Collaboration ^

article info abstract

Article history:Received 1 October 2012Received in revised form 12 February 2013Accepted 28 February 2013Available online 13 March 2013Editor: H. Weerts

A search is performed for collimated muon pairs displaced from the primary vertex produced in the decay of long-lived neutral particles in proton–proton collisions at s = 7 TeV centre-of-mass energy, with the ATLAS detector at the LHC. In a 1.9 fb-1event sample collected during 2011, the observed data are consistent with the Standard Model background expectations. Limits on the product of the production cross section and the branching ratio of a Higgs boson decaying to hidden-sector neutral long-lived particles are derived as a function of the particles' mean lifetime.

© 2013 CERN. Published by Elsevier B.V. Open access under CC BY-NC-ND license.

1. Introduction

A search is presented for long-lived neutral particles decaying to final states containing collimated muon pairs in proton–proton collisions at s = 7 TeV centre-of-mass energy. The event sample, collected during 2011 at the LHC with the ATLAS detector, corresponds to an integrated luminosity of 1.9 fb-1. The model considered in this analysis consists of a Higgs boson decaying to a new hidden sector of particles which finally produce two sets of collimated muon pairs, but the search described is equally valid for other, distinct models such as heavier Higgs boson doublets or singlet scalars, produced through gluon fusion, that decay to a hidden sector and eventually produce collimated muon pairs.

Recently, evidence for the production of a boson with a mass of about 126 GeV has been published by ATLAS [1] and CMS [2]. The observation is compatible with the expected production and decay of the Standard Model (SM) Higgs boson [3–5] at this mass. Testing the SM Higgs hypothesis is currently of utmost importance. To this end two effects may be considered: (i) additional resonances which arise in an extended Higgs sector found in many extensions of the SM, or (ii) rare Higgs boson decays which may deviate from those predicted by the SM. In this Letter we search for a scalar, produced through gluon fusion, that decays to a light hidden sector, according to the topology of Fig. 1, focusing on the 100 GeV to 140 GeV mass range.

The phenomenology of light hidden sectors has been studied extensively over the past few years [6–10]. Possible characteristic topological signatures of such extensions of the SM are “lepton jets”. A lepton jet is a cluster of highly collimated particles: electrons, muons and possibly pions [7,11–13]. These arise if light un-

^ E-mail address: atlas.publications@cern.ch.

stable particles with masses in the MeV to GeV range (for example dark photons, γd ) reside in the hidden sector and decay predominantly to SM particles. At the LHC, hidden-sector particles may be produced with large boosts, causing the visible decay products to form jet-like structures. Hidden-sector particles such as γd may be long-lived, resulting in decay lengths comparable to, or larger than, the detector dimensions. The production of lepton jets can occur through various channels. For instance, in supersymmetric models, the lightest visible superpartner may decay into the hidden sector. Alternatively, a scalar particle that couples to the visible sector may also couple to the hidden sector through Yukawa couplings or the scalar potential. This analysis is focused on the case where the Higgs boson decays to the hidden sector [14,15]. The SM Higgs boson has a narrow width into SM final states if mH < 2mW .Consequently, any new (non-SM) coupling to additional states, which reside in a hidden sector, may contribute significantly to the Higgs boson decay branching ratios. Even with new couplings, the total Higgs boson width is typically small, well below the order of one GeV. If a SM-like Higgs boson is confirmed, it will remain important to constrain possible rare decays, e.g. into lepton jets.

Neutral particles with large decay lengths and collimated final states represent, from an experimental point of view, a challenge both for the trigger and for the reconstruction capabilities of the detector. Collimated particles in the final state can be hard to disentangle due to the finite granularity of the detectors; moreover, in the absence of inner tracking detector information and a primary vertex constraint, it is difficult to reconstruct charged-particle tracks from decay vertices far from the interaction point (IP). The ATLAS detector [16] is equipped with a muon spectrometer (MS) with high-granularity tracking detectors that allow charged- particle tracks to be reconstructed in a standalone configuration using only the muon detector information (MS-only). This is a crucial feature for detecting muons not originating from the primary interaction vertex.

0370-2693/ © 2013 CERN. Published by Elsevier B.V. Open access under CC BY-NC-ND license. http://dx.doi.org/10.1016/j.physletb.2013.02.058

http://dx.doi.org/10.1016/j.physletb.2013.02.058http://www.ScienceDirect.com/http://www.elsevier.com/locate/physletbhttp://creativecommons.org/licenses/by-nc-nd/4.0/mailto:atlas.publications@cern.chhttp://creativecommons.org/licenses/by-nc-nd/4.0/http://dx.doi.org/10.1016/j.physletb.2013.02.058

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 33

Fig. 1. Schematic picture of the Higgs boson decay chain, H → 2( fd2 → fd1γd ).The Higgs boson decays to two hidden fermions ( f d2 ). Each hidden fermion decays to a γd and to a stable hidden fermion ( fd1 ), resulting in two muon jets from the γd decays in the final state.

The search presented in this Letter focuses on neutral particles decaying to the simplest type of muon jets (MJs), containing only two muons; prompt MJ searches have been performed both at the Tevatron [17,18] and at the LHC [19]. Other searches for displaced decays of a light Higgs boson to heavy fermion pairs have also been performed at the LHC [20].

The benchmark model used for this analysis is a simplified scenario where the Higgs boson decays to a pair of neutral hidden fermions ( fd2 ) each of which decays to one long-lived γd and one stable neutral hidden fermion ( fd1) that escapes the detector unnoticed, resulting in two lepton jets from the γd decays in the final state (see Fig. 1). The mass of the γd (0.4 GeV) is chosen to provide a sizeable branching ratio to muons [14].

2. The ATLAS detector

ATLAS is a multi-purpose detector [16] at the LHC, consisting of an inner tracking system (ID) embedded in a superconducting solenoid, which provides a 2 T magnetic field parallel to the beam direction, electromagnetic and hadronic calorimeters and a muon spectrometer using three air-core toroidal magnet systems.1 The trigger system has three levels [21] called Level-1 (L1), Level-2 (L2) and Event Filter (EF). L1 is a hardware-based system using information from the calorimeter and muon spectrometer, and defines one or more Regions of Interest (ROIs), geometrical regions of the detector, identified by (η,φ) coordinates, containing interesting physics objects. L2 and the EF (globally called the High Level Trigger, HLT) are software-based systems and can access information from all sub-detectors. The ID, consisting of silicon pixel and micro-strip detectors and a straw-tube tracker, provides precision tracking of charged particles for |η| ^ 2.5. The electromagnetic and hadronic calorimeter system covers |η| ^ 4.9 and, at η = 0, has a total depth of 9.7 interaction lengths (22 radiation lengths in the electromagnetic part). The MS provides trigger information (|η| ^ 2.4) and momentum measurements (|η| ^ 2.7) for charged particles entering the spectrometer. It consists of one barrel and two endcap parts, each with 16 sectors in φ , equipped with precision tracking chambers and fast detectors for triggering. Monitored drift tubes are used for precision tracking in the region |η| ^ 2.0 and cathode strip chambers are used for 2.0 ^ |η| ^ 2.7. The MS detectors are arranged in three stations of increasing distance from the IP: inner, middle and outer. The air core toroidal magnetic field allows an accurate charged particle reconstruction independent of the ID information. The three planes of trigger chambers (resistive

1 ATLAS uses a right-handed coordinate system with its origin at the nominal interaction point (IP) in the centre of the detector and the z -axis coinciding with the beam pipe axis. The x -axis points from the IP to the centre of the LHC ring, and the y -axis points upward. Cylindrical coordinates (r,φ) are used in the transverse plane, φ being the azimuthal angle around the beam pipe. The pseudorapidity is defined in terms of the polar angle θ as η =-ln tan(θ/2).

Table 1Parameters used for the Monte Carlo simulation. The last column is the γd mean lifetime τ multiplied by the speed of light c , expressed in mm.

Higgs mass[GeV]

mfd2[GeV]

mfd1[GeV]

γd mass[GeV]

cτ[mm]

100 5.0 2.0 0.4 47140 5.0 2.0 0.4 36

plate chambers in the barrel and thin gap chambers in the endcaps) are located in middle and outer (only in the barrel) stations. The L1 muon trigger requires hits in the middle stations to create a low transverse momentum (pT )muonROIorhitsinboth the middle and outer stations for a high p T ROI. The muon ROIs have a spatial extent of 0.2 × 0.2 (^η × ^φ) in the barrel and of 0.1 × 0.1 in the endcap. L1 ROI information seeds, at HLT level, the reconstruction of muon momenta using the precision chamber information. In this way sharp trigger thresholds up to 40 GeV can be obtained.

3. Signal and background simulation

The set of parameters used to generate the signal Monte Carlo samples is listed in Table 1. The Higgs boson is generated through the gluon–gluon fusion production mechanism which is the dominant process for a low mass Higgs boson. The gluon–gluon fusion Higgs boson production cross section in pp collisions at s = 7 TeV, estimated at the next-to-next-to-leading order (NNLO) [22], is σSM = 24.0 pb for mH = 100 GeV and σSM = 12.1 pb formH = 140 GeV. The PYTHIA generator [23] is used, linked together with MadGraph4.4.2 [24] and BRIDGE [25], for gluon–gluon fusion production of the Higgs boson and the subsequent decay to hidden-sector particles.

As discussed in the introduction, the signal is chosen to enable a study of rare, non-SM, Higgs boson decays in the (possibly extended) Higgs sector. To do so we choose two points which envelope a mass range covering the 126 GeV resonance. The lower mass point, mH = 100 GeV, is chosen to be compatible with the decay-mode-independent search by OPAL at LEP [26]. The higher mass point, mH = 140 GeV, is chosen well below the WW threshold, where a sizeable branching ratio into a hidden sector may be naturally achieved. The masses of f d2 and fd1 are chosen to be light relative to the Higgs boson mass, and far from the kinematic threshold at m fd1 + mγd = m fd2. For the chosen dark photon mass (0.4 GeV), the γd decay branching ratios are expected to be [14]: 45% e+e-, 45% μ+μ-,10%π +π -. Thus 20% of the Higgs H → γd γd + X decays are expected to have the required four-muon final state.

The mean lifetime τ of the γd (expressed throughout this Letter as τ times the speed of light c ) is a free parameter of the model. In the generated samples cτ is chosen so that a large fraction of the decays occur inside the sensitive ATLAS detector volume, i.e. up to 7 m in radius and 13 m along the z -axis, where the trigger chambers of the middle stations are located. The detection efficiency can then be estimated for a range of γd mean lifetimes through re-weighting of the generated samples.

Potential backgrounds include all the processes which lead to real prompt muons in the final state such as the SM processes W + jets, Z + jets, tt¯, WW, WZ, and ZZ. However, the main contribution to the background is expected from processes giving a high production rate of secondary muons which do not point to the primary vertex, such as decays in flight of K /π and heavy flavour decays in multi-jet processes, or muons due to cosmic rays. The prompt lepton background samples are generated using PYTHIA (W + jets, and Z + jets) and MC@NLO [27] (tt¯, WW, WZ, and ZZ).

34 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

Fig. 2. ^ R distribution between the two muons from the γd decay for the signal Monte Carlo samples with m H = 100 GeV and mH = 140 GeV.

The generated Monte Carlo events are processed through the full ATLAS simulation chain based on GEANT4 [28,29]. Additional pp interactions in the same and nearby bunch crossings (pile-up) are included in the simulation. All Monte Carlo samples are reweighted to reproduce the observed distribution of the number of interactions per bunch crossing in the data. For the multi-jet background evaluation a data-driven method is used. The cosmic-ray background is also evaluated from data.

4. The kinematics of the signal

The main kinematic characteristics of the signal sample are:

• The γd pair are emitted approximately back-to-back in φ ,with an angular spread of the distribution due to the emission of the fd1.

• The average p T of the γd in the laboratory frame is about 20 GeV for mH = 100 GeV and 30 GeV for mH = 140 GeV; due to the small mass of the γd , large boost factors in the decay length should be expected.

• Fig. 2 shows the distribution of ^ R = (^η)2 + (^φ)2 between the two muons from the γd decay. The ^ R is computed at the decay vertex of the γd from the vector momenta of the two muons. Due to the small mass of the γd the ^ R is almost always below 0.1.

2 High pile-up levels will introduce a pile-up dependence for the isolation variables used in the analysis and needs to be further investigated.

Since the two fd1 are, like the two γd , emitted back-to-back in φ , the observed missing transverse momentum E Tmiss , computed at the event-generator level, is small and cannot be used as a discriminating variable against the background.

5. Data samples and trigger selection

The dataset used for this analysis was collected at a centre-of- mass energy of 7 TeV during the first part of 2011, where a low level of pile-up events in the same bunch-crossing was present (an average of ≈ 6 interactions per crossing).2 Only periods in which all ATLAS subdetectors were operational are used. The total integrated luminosity used is 1.94 ± 0.07 fb-1 [30,31]. All events are required to have at least one reconstructed vertex along the beam line with at least three associated tracks, each with pT ^ 0.4 GeV. The primary interaction vertex is defined to be the vertex whose constituent tracks have the largest pT2 . This analysis deals with displaced γd decays with final states containing only muons. Signal events are therefore characterized by a four-muon final state

with the four muons coming from two displaced decay vertices. Due to the relatively low p T of the muons and due to the displaced decay vertex, a low-pT multi-muon trigger with muons reconstructed only in the MS is needed. In order to have an acceptably low trigger rate at a low pT threshold, a multiplicity of at least three muons is required. Candidate events are collected using an unprescaled HLT trigger with three reconstructed muons of p T ^ 6 GeV, seeded by a L1-accept with three different muon ROIs. These muons are reconstructed only in the MS, since muons originating from a neutral particle decaying outside the pixel detector will not have a matching track in the ID tracking system. The trigger efficiency for the Monte Carlo signal samples, defined as the fraction of events passing the trigger requirement with respect to the events satisfying the analysis selection criteria (described in Section 6) is 0.32 ± 0.01stat for mH = 100 GeV and 0.31 ± 0.01stat for mH = 140 GeV.

The main reason for the relatively low trigger efficiency is the small opening ^ R between the two muons of the γd decay (^ R ^ 0.1) shown in Fig. 2. These values of ^ R are often smaller than the L1 trigger granularity; in this case the L1 produces only one ROI. The trigger only fires if at least one of the γd produces two distinct L1 ROIs. The single γd ROI efficiency, ε2ROI (ε1ROI), defined as the fraction of γd passing the offline selection that give two (one) trigger ROIs is 0.296 ± 0.004stat (0.626±0.004stat) for mH =100 GeV and 0.269 ± 0.003stat (0.653±0.003stat)formH =140 GeV. Fig. 3 shows the ε2ROI as a function of the dark photon η and of the ^ R of the two muons from the γd decay. The increased trigger granularity in the endcap and the efficiency decrease at small values of ^ R are clearly visible.

The systematic uncertainty on the trigger efficiency is estimated with a sample of J /ψ → μ+μ- from collision data and a corresponding sample of Monte Carlo events, using the tag-and-probe (TP) method. A cut on ^ R ^ 0 . 1 between the two muons is used to reproduce the small track-to-track spatial separation in the MS of the signal. The tag is a (MS + ID) combined muon, defined as a MS-reconstructed muon that is associated with a trigger object and combined with a matching “good ID track”. Good ID tracks must have at least one hit in the pixel detector, at least six hits in the silicon micro-strip detectors and at least six hits in the strawtube tracker. The probe is a good ID track which, when combined with the tag track, gives an invariant mass inside a 100 MeV window around the J /ψ mass. A muon ROI that matches the probe in η and φ , and is different from the ROI associated with the tag, is searched for. The number of probes with a matched ROI divided by the number of probes without a matched ROI gives the ε2TPROI/ε1TRPOI ratio. Values of ε2TRPOI/ε1TRPOI = 0.42 ± 0.05stat for the J/ψ → μ+μ- data and ε2TRPOI/ε1TPROI = 0.39 ± 0.05stat for the corresponding Monte Carlo sample are obtained. The relative statistical uncertainty on the difference between these two estimates is 17% and this is taken conservatively to be the systematic uncertainty on the trigger efficiency.

6. Muon Jet reconstruction and event selection

MJs from displaced γd decays are characterized by a pair of muons in a narrow cone, produced away from the primary vertex of the event. Consequently tracks reconstructed in the MS with a good quality track fit [32] are used. MJs are identified using a simple clustering algorithm that associates all the muons in cones of ̂R = 0.2, starting with the muon with highest p T.Thesizeof the cone takes into account the multiple scattering of the muons in the calorimeters. All the muons found in the cone are associated with a MJ. After this procedure, if any muons are unassociated with a MJ the search is repeated for this remainder, starting again with the highest pT muon. This continues until all possible MJs

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 35

Fig. 3. ε2ROI as a function (a) of the η of the γd and (b) of the ^ R of the muon pair for the Monte Carlo samples with Higgs boson masses of 100 GeV and 140 GeV. The errors are statistical only.

are formed. The MJ direction and momentum are obtained from the vector sum over all muons in the MJ. Only MJs with two reconstructed muons are accepted and only events with two MJs are kept for the subsequent analysis. In order to keep the search as model independent as possible no requirement on the muon momenta has been introduced.

The possible contribution to the background of SM processes which lead to real prompt muon pairs in the final state is evaluated using simulated samples. After the trigger and the requirement of having two MJs in the event, their contributions have been found to be negligible. The only significant background sources are expected to be from processes giving a high production rate of secondary muons which do not point to the primary vertex, such as decays in flight of K /π and heavy flavour decays in multi-jet production, or cosmic-ray muons not pointing to the primary vertex.

In order to separate the signal from the background, a number of discriminating variables have been studied. The multi-jet background can be significantly reduced by using calorimeter isolation requirements around the MJ direction. The calorimetric isolation variable E iTsol is defined as the difference between the transverse calorimetric energy E T in a cone of ^R = 0.4 around the highest pT muon of the MJ and the E T in a cone of ^R = 0.2; a cut E iTsol ^ 5 GeV keeps almost all the signal. The isolation modelling is validated for real isolated muons with a sample of muons coming from Z → μμ decays. To further improve the signal-to-background ratio, two additional discriminating variables are used: ^φ between the two MJs and p ITD for the MJ, defined as the scalar sum of the transverse momentum of the tracks, measured in the ID, inside a cone ^ R = 0.4 around the direction of the MJ. The muon tracks of the MJ in the ID, if any, are not removed from the isolation sum, so that prompt muons, which give a reconstructed track in both the ID and MS, will contribute to the p ITD.Asa consequence a cut on p ITD of a few GeV will remove prompt MJs or MJs with very short decay length.

For the background coming from cosmic-ray muons (mainly pairs of almost parallel cosmic-ray muons crossing the detector) a cut on the impact parameters of the muon tracks with respect to the primary interaction vertex is used.

The final set of selection criteria used is the following:

• Topology cut: events are required to have exactly two MJs, N MJ = 2.

• MJ isolation: require MJ isolation with E Tisol ^ 5GeV for both MJs in the event.

• Require |^φ| ^ 2 between the two MJs.• Require opposite charges for the two muons in a MJ (QMJ = 0).• Require a cut on the transverse and longitudinal impact pa

rameters of the muons with respect to the primary vertex: |d0 | < 200 mm and |z0 | < 270 mm.

• Require ^ p ITD < 3GeVforbothMJs.

The distributions of the relevant variables used in the selection before each step of the cut flow are shown in Fig. 4. The results are summarized in Table 2. No events survive the selection in the data sample whereas the expected signals from Monte Carlo simulation, assuming the Higgs boson SM production cross section, 100% branching ratio for H → γd γd + X and the parameters given in Table 1, are 75 or 48 events for Higgs boson masses of 100 GeV and 140 GeV respectively. The method used to estimate the cosmic-ray and multi-jet background yields, quoted in Table 2, is discussed in Section 7.

The resulting single γd reconstruction efficiency for the mean lifetimes given in Table 1 is shown in Fig. 5 as a function of η,the ^ R separation of the two muons from the γd decay and the decay length in the transverse plane, Lxy,oftheγd . The efficiency is defined as the number of γd passing the offline selection divided by the number of γd in the spectrometer acceptance (|η| ^ 2.4) with both muons having pT ^ 6 GeV. The low reconstruction efficiency at very short Lxy is a consequence of the pITD cut.

The systematic uncertainty on the reconstruction efficiency is evaluated using a tag-and-probe method by comparing the reconstruction efficiency εrTePc for J /ψ → μ+μ- samples from collision data and J /ψ → μ+μ- Monte Carlo simulation. The tag-and- probe definitions and the cut on ^ R ^ 0.1 between the two muons are the same as in Section 5. To measure the reconstruction efficiency the ID probe track is associated with a MS-only muon track, different from the one associated with the tag. The result is shown in Fig. 6.

The relative difference between the result obtained from the J /ψ → μ+μ- data and the J /ψ → μ+μ- Monte Carlo sample in the same range of ^ R ^ 0.1, as for the signal, is taken as the systematic uncertainty on the reconstruction efficiency and amounts to 13%.

7. Multi-jet and cosmic-ray background evaluation

To estimate the multi-jet background contamination in the signal region we use a data-driven ABCD method slightly modified to cope with the problem of the very low number of events in the control regions. The ABCD method assumes that two variables can be identified, which are relatively uncorrelated, and which can each be used to separate signal and background. It is assumed that the multi-jet background distribution can be factorized in the MJ EiTsol–|^φ| plane. The region A is defined by ETisol ^ 5 GeV and |^φ| < 2; the region B, defined by E iTsol ^ 5 GeV and |^φ| ^ 2, is the signal region. The regions C and D are the anti-isolated regions ( E iTsol > 5 GeV) and they are defined by |^φ| < 2 and |^φ| ^ 2, respectively. Neglecting the signal contamination in regions A, C and

36 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

Fig. 4. Plots of the variables used in the selection before the corresponding cut on Monte Carlo (m H = 140 GeV) and on data. The arrows indicate in each plot the position of the cut. (a) Distribution of the calorimetric isolation around the MJ direction E iTsol after the requirement of two MJs in the event. (b) Distribution of ^φ between the two MJs after the requirement of the isolation cut. (c) Distribution of p ITD of the MJ after the requirement of the impact parameters cut. The points show the data and the histogram is the signal Monte Carlo normalized to 1.9 fb-1 . The uncertainties are statistical only.

Table 2Cut flow for the event selection on the cosmic-ray background, the multi-jet background estimation from the ABCD method (described in Section 7), the signal Monte Carlo and the data; the background event and signal yields are normalized to an integrated luminosity of 1.9 fb-1 . The signal yields assume the Higgs boson SM production cross sections at the two mass values and 100% branching ratio of H → γd γd + X . The first uncertainties are statistical and the second systematic.

Cut Cosmic-rays Multi-jet Total background m H = 100 GeV mH =140 GeV Data

N MJ = 2 3.0± 2.1 N/A N/A 135± 11+-2291 90± 9-+1173 871EiTsol ^5GeV 3.0± 2.1 N/A N/A 132± 11-+2281 88± 9-+1173 219|^φ|^2 1.5 ± 1.5 153±18±9 155± 18± 9 123± 11-+1269 81± 9-+1152 104

QMJ = 0 1.5 ± 1.5 57± 15± 22 59±15±22 121± 11+-2169 79± 8-+1152 80|d0 |, |z0 | 0+1.640-0 111±39±63 111± 39± 63 105 ± 10-+1226 66± 8-+1120 70^ p ITD < 3GeV 0+1.640-0 0.06 ± 0.02-+00..6066 0.06+1.64+0.660.06-0.02-0.06 75± 9-+1162 48± 7+-97 0

D(E iTsol > 5GeVor|^φ| < 2) the number of multi-jet background events in the signal region can be evaluated as NB = ND × NA/NC. Due to the very low number of events in the control regions the values of N A, NC and ND as a function of the cut on the final discriminant variable pITD are extracted by modelling the pITD distributions with bifurcated Gaussian templates, with parameters fitted from the data in the corresponding regions, and by integrating the fitted function in the range 0 < pITD < 3GeV. The low statistics in the four regions at each step of the cut flow results in large fluctuations in the multi-jet background estimate; however, the expected contribution to the final number of background events is negligible and the statistical uncertainty on the data driven background is included in the systematic. The extracted yields are NA = (7.1±1.5stat)·10-3, NC = (1.81±1.0stat)·10-2 and ND = (1.51±0.07stat)·10-1 and the estimated number of multi-jet background events in the signal region is N B = 0.06 ± 0.02stat.

Possible sources of systematic uncertainty related to the background estimation method are also evaluated. Various functional models are used to fit the p ITD distributions, trying extremefunctional forms from linear distribution to bifurcate Gaussian in order to get an estimate of the uncertainty on the number of multi-jet background events in each control region. The procedure to estimate the number of multi-jet background events in the signal region is then repeated. The maximum variation in N B is taken as the systematic uncertainty, that amounts to +00..6066. The effect of possible signal leakage in the background regions is also considered and is found to be negligible.

The background induced by muons from cosmic-ray showers is evaluated using events collected by the trigger being active when there are no collisions (empty bunch crossings). The number of triggered events is rescaled by the collision to empty bunch crossing ratio and for the active time (since the trigger in the empty bunch crossing was not active in all the runs). No events survived the requirements on the impact parameters with respect to the primary vertex (|d0 | < 200 mm and | z0 | < 270 mm), resulting in a

cosmic-ray contamination estimate of 0+01.64. The final yields for the different background sources are summarized in Table 2.

8. Systematic uncertainties

The following effects are considered as possible sources of systematic uncertainty:

• LuminosityThe overall normalization uncertainty of the integrated luminosity is 3.7% [30,31].

• Muon momentum resolutionThe systematic uncertainty on the muon momentum resolution for MS-only muons has been evaluated by smearing and shifting the momenta of the muons by scale factors derived from Z → μμ data-Monte Carlo comparison, and by observing the effect of this shift on the signal efficiency. The overall effect of the muon momentum resolution uncertainty is negligible.

• TriggerThe systematic uncertainty on the single γd trigger efficiency, evaluated using a tag-and-probe method is 17% (see Section 5).

• Reconstruction efficiencyThe systematic uncertainty on the reconstruction efficiency, evaluated using a tag-and-probe method for the single γd reconstruction efficiency, is 13% (see Section 6).

• Effect of pile-upThe systematic uncertainty on the signal efficiency related to the effect of pile-up is evaluated by comparing the number of signal events after imposing all the selection criteria on the signal Monte Carlo sample increasing the average number of interactions per crossing from ≈ 6to≈ 16. This systematic uncertainty is negligible.

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 37

Fig. 5. γd reconstruction efficiency εrec as a function (a) of η,(b)of ̂R and (c) of the transverse decay length of the γd for m H = 100 GeV and mH = 140 GeV and for the mean lifetimes given in Table 1. The reconstruction efficiency is defined as the number of γd passing the offline selection divided by the number of γd in the spectrometer acceptance ( |η | ^ 2.4) with both muons having p T ^ 6GeV. The uncertainties are statistical only.

Fig. 6. Tag-and-probe reconstruction efficiency εrTePc as a function of the ̂R between the two muons, evaluated on a sample of J /ψ → μ+μ- from collision data and a corresponding sample of Monte Carlo events. The εrTePc for the signal Monte Carlo, evaluated with a similar tag-and-probe method, is also shown. The uncertainties are statistical only.

Table 3Ranges in which γd cτ is excluded at 95% CL for m H = 100 GeV and m H = 140 GeV, assuming 100% and 10% branching ratio of H → γd γd + X and the SM Higgs boson production cross section.

Higgs boson mass [GeV]

Excluded cτ [mm]BR(100%)

Excluded cτ [mm]BR(10%)

100 1 ^ c τ ^ 670 5 ^ c τ ^ 159140 1 ^ c τ ^ 430 7 ^ c τ ^ 82

• Effect of p ITD cutSince the p ITD cut could affect the minimum cτ value thatcan be excluded, the effect of this cut on the signal Monte Carlo has been studied. A variation of 10% on the p ITD cut results in a relative variation of

38 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

Fig. 7. The 95% upper limits on the σ × BR for the process H → γd γd + X as a function of the dark photon cτ for the benchmark sample with (a) m H = 100 GeV and with (b) m H = 140 GeV, assuming the Higgs boson SM production cross section. The expected limit is shown as the dashed curve and the solid curve shows the observed limit. The horizontal lines correspond to the Higgs boson SM production cross sections at the two mass values.

on the σ × BR of a 126 GeV Higgs boson may be conservatively extracted using the corresponding 140 GeV exclusion curve.

Acknowledgements

We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently.

We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Nor

way; MNiSW, Poland; GRICES and FCT, Portugal; MERYS (MECTS), Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MVZT, Slovenia; DST/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, United Kingdom; DOE and NSF, United States of America.

The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA) and in the Tier-2 facilities worldwide.

Open access

This article is published Open Access at sciencedirect.com. It is distributed under the terms of the Creative Commons Attribution License 3.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.

References

[1] ATLAS Collaboration, Phys. Lett. B 716 (2012) 1, arXiv:1207.7214.[2] CMS Collaboration, Phys. Lett. B 716 (2012) 30, arXiv:1207.7235.[3] F. Englert, R. Brout, Phys. Rev. Lett. 13 (1964) 321.[4] P.W. Higgs, Phys. Lett. 12 (1964) 132.[5] G.S. Guralnik, C.R. Hagen, T.W.B. Kibble, Phys. Rev. Lett. 13 (1964) 585.[6] M.J. Strassler, K.M. Zurek, Phys. Lett. B 651 (2007) 374, arXiv:hep-ph/0604261.[7] N. Arkani-Hamed, N. Weiner, JHEP 0812 (2008) 104, arXiv:0810.0714.[8] T. Han, Z. Si, K.M. Zurek, M.J. Strassler, JHEP 0807 (2008) 008.[9] S. Gopalakrishna, S. Jung, J.D. Wells, Phys. Rev. D 78 (2008) 055002, arXiv:

0801.3456.[10] M.J. Strassler, K.M. Zurek, Phys. Lett. B 661 (2008) 263, arXiv:hep-ph/0605193.[11] M. Baumgart, C. Cheung, J.T. Ruderman, L.T. Wang, I. Yavin, JHEP 0904 (2009)

014, arXiv:0901.0283.[12] C. Cheung, J.T. Ruderman, L.T. Wang, I. Yavin, JHEP 1004 (2010) 116, arXiv:

0909.0290.[13] Y. Bai, Z. Han, Phys. Rev. Lett. 103 (2009) 051801, arXiv:0902.0006.[14] A. Falkowski, J.T. Ruderman, T. Volansky, J. Zupan, JHEP 1005 (2010) 077.[15] A. Falkowski, J.T. Ruderman, T. Volansky, J. Zupan, Phys. Rev. Lett. 105 (2010)

241801, arXiv:1007.3496.[16] ATLAS Collaboration, JINST 3 (2008) S08003.[17] V.M. Abazov, et al., D0 Collaboration, Phys. Rev. Lett. 103 (2009) 081802.[18] V.M. Abazov, et al., D0 Collaboration, Phys. Rev. Lett. 105 (2010) 211802.[19] CMS Collaboration, JHEP 1107 (2011) 098, arXiv:1106.2375.[20] ATLAS Collaboration, Phys. Rev. Lett. 108 (2012) 251801.[21] ATLAS Collaboration, Eur. Phys. J. C 72 (2012) 1849, arXiv:1110.1530.[22] LHC Higgs Cross Section Working Group, S. Dittmaier, C. Mariotti, G. Passarino,

R. Tanaka (Eds.), Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables, CERN-2011-002, CERN, Geneva, 2011, arXiv:1101.0593.

[23] S. Mrenna, T. Sjöstrand, P.Z. Skands, JHEP 0605 (2006) 026, arXiv:hep-ph/ 0603175.

[24] J. Alwall, M. Herquet, F. Maltoni, O. Mattelaer, T. Stelzer, JHEP 1106 (2011) 128, arXiv:1106.0522.

[25] P. Meade, M. Reece, Bridge: Branching Ratio Inquiry/Decay Generated Events, arXiv:hep-ph/0703031.

[26] G. Abbiendi, et al., OPAL Collaboration, Eur. Phys. J. C 27 (2003) 311, arXiv: hep-ex/0206022.

[27] S. Frixione, B.R. Webber, JHEP 0206 (2002) 029, arXiv:hep-ph/0204244.[28] S. Agostinelli, et al., Nucl. Instrum. Meth. A 506 (2003) 250.[29] ATLAS Collaboration, Eur. Phys. J. C 70 (2010) 823, arXiv:1005.4568.[30] ATLAS Collaboration, Eur. Phys. J. C 71 (2011) 1630, arXiv:1101.2185.[31] ATLAS Collaboration, Luminosity determination in pp collisions at s = 7TeV

using the ATLAS detector in 2011, ATLAS-CONF-2011-116, http://cdsweb.cern. ch/record/1376384/files/ATLAS-CONF-2011-116.pdf.

[32] ATLAS Collaboration, Expected performance of the ATLAS experiment – detector, trigger and physics, arXiv:0901.0512, 2009.

[33] A.L. Read, J. Phys. G 28 (2002) 2693.

http://www.sciencedirect.comhttp://cdsweb.cern.ch/record/1376384/files/ATLAS-CONF-2011-116.pdfhttp://cdsweb.cern.ch/record/1376384/files/ATLAS-CONF-2011-116.pdf

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 39

ATLAS Collaboration

G. Aad 47, T. Abajyan20, B. Abbott 110, J. Abdallah 11, S. Abdel Khalek 114, A.A. Abdelalim48, O. Abdinov10,R. Aben104,B.Abi111,M.Abolins87, O.S. AbouZeid 157, H. Abramowicz152, H. Abreu135, E. Acerbi88a,88b,B.S. Acharya 163a,163b, L. Adamczyk37, D.L. Adams 24, T.N. Addy 55, J. Adelman175, S. Adomeit97, P. Adragna 74, T. Adye128, S. Aefsky22, J.A. Aguilar-Saavedra 123b,a, M. Agustoni16, M. Aharrouche80,S.P. Ahlen 21, F. Ahles47, A. Ahmad147, M. Ahsan40, G. Aielli 132a,132b, T. Akdogan 18a, T.P.A. Åkesson 78,G. Akimoto 154, A.V. Akimov 93, M.S. Alam1, M.A. Alam75, J. Albert168, S. Albrand54, M. Aleksa29,I.N. Aleksandrov 63, F. Alessandria88a, C. Alexa25a, G. Alexander152, G. Alexandre48, T. Alexopoulos9,M. Alhroob163a,163c, M. Aliev15, G. Alimonti88a, J. Alison 119, B.M.M. Allbrooke 17, P.P. Allport 72, S.E. Allwood-Spiers 52, J. Almond81, A. Aloisio101a,101b, R. Alon171, A. Alonso78, F. Alonso69,B. Alvarez Gonzalez 87, M.G. Alviggi 101a,101b, K. Amako64, C. Amelung22, V.V. Ammosov 127,∗,S.P. Amor Dos Santos123a, A. Amorim123a,b, N. Amram152, C. Anastopoulos 29, L.S. Ancu16, N. Andari114,T. Andeen 34, C.F. Anders57b, G. Anders57a, K.J. Anderson 30, A. Andreazza 88a,88b, V. Andrei57a,M.-L. Andrieux 54, X.S. Anduaga69, P. Anger43, A. Angerami34, F. Anghinolfi 29, A. Anisenkov 106,N. Anjos 123a, A. Annovi46, A. Antonaki8, M. Antonelli46, A. Antonov95, J. Antos143b, F. Anulli 131a,M. Aoki100, S. Aoun82, L. Aperio Bella 4, R. Apolle 117,c, G. Arabidze87, I. Aracena142, Y. Arai64,A.T.H. Arce44, S. Arfaoui147, J.-F. Arguin 14, E. Arik18a,∗, M. Arik18a, A.J. Armbruster86, O. Arnaez 80, V. Arnal 79, C. Arnault114, A. Artamonov94, G. Artoni131a,131b, D. Arutinov 20, S. Asai154,R. Asfandiyarov 172, S. Ask27, B. Åsman145a,145b, L. Asquith5, K. Assamagan24, A. Astbury168,M. Atkinson 164, B. Aubert4, E. Auge114, K. Augsten 126, M. Aurousseau144a, G. Avolio162, R. Avramidou 9,D. Axen 167, G. Azuelos92,d, Y. Azuma154, M.A. Baak 29, G. Baccaglioni 88a, C. Bacci 133a,133b, A.M. Bach14,H. Bachacou 135, K. Bachas29, M. Backes48, M. Backhaus20, E. Badescu25a, P. Bagnaia131a,131b,S. Bahinipati2, Y. Bai32a, D.C. Bailey157, T. Bain157, J.T. Baines128, O.K. Baker175, M.D. Baker24, S. Baker 76, E. Banas 38, P. Banerjee 92, Sw. Banerjee 172, D. Banfi29, A. Bangert149, V. Bansal168,H.S. Bansil 17, L. Barak 171, S.P. Baranov 93, A. Barbaro Galtieri14, T. Barber47, E.L. Barberio 85,D. Barberis49a,49b, M. Barbero20, D.Y. Bardin63, T. Barillari 98, M. Barisonzi 174, T. Barklow142,N. Barlow 27, B.M. Barnett 128, R.M. Barnett 14, A. Baroncelli 133a, G. Barone48, A.J. Barr117, F. Barreiro 79,J. Barreiro Guimarães da Costa 56, P. Barrillon 114, R. Bartoldus142, A.E. Barton70, V. Bartsch148,A. Basye164, R.L. Bates52, L. Batkova143a, J.R. Batley27, A. Battaglia16, M. Battistin 29, F. Bauer 135,H.S. Bawa 142,e, S. Beale97, T. Beau77, P.H. Beauchemin 160, R. Beccherle49a, P. Bechtle20, H.P. Beck16,A.K. Becker174, S. Becker97, M. Beckingham 137, K.H. Becks174, A.J. Beddall 18c, A. Beddall 18c, S. Bedikian 175, V.A. Bednyakov63, C.P. Bee82, L.J. Beemster 104, M. Begel 24, S. Behar Harpaz 151, P.K. Behera 61, M. Beimforde98, C. Belanger-Champagne 84, P.J. Bell48, W.H. Bell48, G. Bella 152,L. Bellagamba 19a, F. Bellina 29, M. Bellomo 29, A. Belloni 56, O. Beloborodova 106,f , K. Belotskiy95,O. Beltramello 29, O. Benary152, D. Benchekroun 134a, K. Bendtz145a,145b, N. Benekos 164, Y. Benhammou 152, E. Benhar Noccioli 48, J.A. Benitez Garcia 158b, D.P. Benjamin 44, M. Benoit114,J.R. Bensinger 22, K. Benslama129, S. Bentvelsen104, D. Berge29, E. Bergeaas Kuutmann 41, N. Berger4,F. Berghaus 168, E. Berglund 104, J. Beringer 14, P. Bernat 76, R. Bernhard 47, C. Bernius 24,T.Berry75,C. Bertella 82, A. Bertin19a,19b, F. Bertolucci 121a,121b, M.I. Besana 88a,88b, G.J. Besjes103, N. Besson 135, S. Bethke 98, W. Bhimji45, R.M. Bianchi 29, M. Bianco 71a,71b, O. Biebel 97, S.P. Bieniek76, K. Bierwagen53,J. Biesiada 14, M. Biglietti 133a, H. Bilokon 46, M. Bindi19a,19b, S. Binet114, A. Bingul 18c, C. Bini 131a,131b,C. Biscarat 177, B. Bittner 98, K.M. Black21, R.E. Blair 5, J.-B. Blanchard 135, G. Blanchot29, T. Blazek143a,C. Blocker 22, J. Blocki38, A. Blondel48, W. Blum80, U. Blumenschein53, G.J. Bobbink 104,V.B. Bobrovnikov 106, S.S. Bocchetta78, A. Bocci 44, C.R. Boddy 117, M. Boehler47, J. Boek174, N. Boelaert35,J.A. Bogaerts 29, A. Bogdanchikov 106, A. Bogouch 89,∗,C.Bohm145a,J.Bohm124, V. Boisvert 75,T.Bold37, V. Boldea25a, N.M. Bolnet135, M. Bomben77, M. Bona74, M. Boonekamp135, C.N. Booth138, S. Bordoni77,C. Borer 16, A. Borisov127, G. Borissov 70, I. Borjanovic 12a, M. Borri81, S. Borroni86, V. Bortolotto133a,133b,K. Bos 104, D. Boscherini 19a, M. Bosman 11, H. Boterenbrood104, J. Bouchami92, J. Boudreau122,E.V. Bouhova-Thacker70, D. Boumediene33, C. Bourdarios 114, N. Bousson82, A. Boveia30, J. Boyd29,I.R. Boyko 63, I. Bozovic-Jelisavcic 12b, J. Bracinik17, P. Branchini133a, G.W. Brandenburg56, A. Brandt7,G. Brandt117, O. Brandt53, U. Bratzler155, B. Brau83, J.E. Brau 113, H.M. Braun174,∗, S.F. Brazzale 163a,163c,B. Brelier 157, J. Bremer29, K. Brendlinger 119, R. Brenner 165, S. Bressler 171, D. Britton52, F.M. Brochu27,

40 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

I. Brock 20, R. Brock87, F. Broggi 88a, C. Bromberg87, J. Bronner 98, G. Brooijmans 34, T. Brooks 75, W.K. Brooks 31b, G. Brown81, H. Brown7, P.A. Bruckman de Renstrom 38, D. Bruncko 143b, R. Bruneliere 47, S. Brunet 59, A. Bruni 19a, G. Bruni 19a, M. Bruschi 19a, T. Buanes13, Q. Buat54, F. Bucci 48, J. Buchanan 117,P. Buchholz 140, R.M. Buckingham 117, A.G. Buckley45, S.I. Buda 25a, I.A. Budagov 63, B. Budick 107, V. Büscher80, L. Bugge116, O. Bulekov 95, A.C. Bundock72, M. Bunse42, T. Buran116, H. Burckhart29, S. Burdin 72, T. Burgess13, S. Burke128, E. Busato33, P. Bussey 52, C.P. Buszello 165, B. Butler142,J.M. Butler21, C.M. Buttar52, J.M. Butterworth76, W. Buttinger 27, M. Byszewski29, S. Cabrera Urbán166,D. Caforio 19a,19b, O. Cakir3a, P. Calafiura 14, G. Calderini 77, P. Calfayan97, R. Calkins105, L.P. Caloba23a,R. Caloi131a,131b, D. Calvet33, S. Calvet33, R. Camacho Toro 33, P. Camarri 132a,132b, D. Cameron116,L.M. Caminada 14, R. Caminal Armadans 11, S. Campana29, M. Campanelli 76, V. Canale 101a,101b,F. Canelli 30,g, A. Canepa158a, J. Cantero79, R. Cantrill 75, L. Capasso 101a,101b, M.D.M. Capeans Garrido 29,I. Caprini 25a, M. Caprini 25a, D. Capriotti 98, M. Capua36a,36b, R. Caputo80, R. Cardarelli132a, T. Carli29,G. Carlino 101a, L. Carminati88a,88b, B. Caron84, S. Caron103, E. Carquin31b, G.D. Carrillo-Montoya 172,A.A. Carter74, J.R. Carter27, J. Carvalho123a,h, D. Casadei 107, M.P. Casado 11, M. Cascella 121a,121b,C. Caso 49a,49b,∗, A.M. Castaneda Hernandez 172,i, E. Castaneda-Miranda 172, V. Castillo Gimenez 166,N.F. Castro 123a, G. Cataldi 71a, P. Catastini 56, A. Catinaccio 29, J.R. Catmore 29, A. Cattai29,G. Cattani 132a,132b, S. Caughron 87, V. Cavaliere164, P. Cavalleri 77, D. Cavalli 88a, M. Cavalli-Sforza 11, V. Cavasinni 121a,121b, F. Ceradini 133a,133b, A.S. Cerqueira 23b, A. Cerri29, L. Cerrito74, F. Cerutti 46,S.A. Cetin18b, A. Chafaq134a, D. Chakraborty105, I. Chalupkova125, K. Chan2, P. Chang164, B. Chapleau84,J.D. Chapman 27, J.W. Chapman86, E. Chareyre 77, D.G. Charlton17, V. Chavda 81, C.A. Chavez Barajas 29, S. Cheatham 84, S. Chekanov5, S.V. Chekulaev158a, G.A. Chelkov63, M.A. Chelstowska103, C. Chen62,H. Chen24, S. Chen32c, X. Chen172, Y. Chen34, A. Cheplakov63, R. Cherkaoui El Moursli 134e, V. Chernyatin24, E. Cheu6, S.L. Cheung157, L. Chevalier135, G. Chiefari101a,101b, L. Chikovani 50a,∗,J.T. Childers 29, A. Chilingarov 70, G. Chiodini 71a, A.S. Chisholm17, R.T. Chislett76, A. Chitan25a,M.V. Chizhov 63, G. Choudalakis30, S. Chouridou136, I.A. Christidi 76, A. Christov 47,D. Chromek-Burckhart 29, M.L. Chu150, J. Chudoba124, G. Ciapetti 131a,131b, A.K. Ciftci 3a, R. Ciftci 3a,D. Cinca 33, V. Cindro 73, C. Ciocca 19a,19b, A. Ciocio 14, M. Cirilli 86, P. Cirkovic 12b, Z.H. Citron 171,M. Citterio 88a, M. Ciubancan25a, A. Clark48, P.J. Clark45, R.N. Clarke14, W. Cleland 122, J.C. Clemens 82,B. Clement 54, C. Clement145a,145b, Y. Coadou82, M. Cobal163a,163c, A. Coccaro137, J. Cochran62,J.G. Cogan 142, J. Coggeshall 164, E. Cogneras177, J. Colas4, S. Cole105, A.P. Colijn104, N.J. Collins 17,C. Collins-Tooth 52, J. Collot 54, T. Colombo 118a,118b, G. Colon 83, P. Conde Muiño 123a, E. Coniavitis 117, M.C. Conidi 11, S.M. Consonni 88a,88b, V. Consorti 47, S. Constantinescu 25a, C. Conta118a,118b, G. Conti56, F. Conventi 101a,j, M. Cooke 14, B.D. Cooper 76, A.M. Cooper-Sarkar 117, K. Copic14, T. Cornelissen 174, M. Corradi 19a, F. Corriveau84,k, A. Cortes-Gonzalez 164, G. Cortiana98, G. Costa88a, M.J. Costa166,D. Costanzo138, D. Côté29, L. Courneyea168, G. Cowan75, C. Cowden27, B.E. Cox 81, K. Cranmer107, F. Crescioli 121a,121b, M. Cristinziani 20, G. Crosetti 36a,36b, S. Crépé-Renaudin 54, C.-M. Cuciuc25a,C. Cuenca Almenar 175, T. Cuhadar Donszelmann138, M. Curatolo46, C.J. Curtis17, C. Cuthbert 149, P. Cwetanski 59, H. Czirr140, P. Czodrowski43, Z. Czyczula175, S. D'Auria52, M. D'Onofrio72,A. D'Orazio 131a,131b, M.J. Da Cunha Sargedas De Sousa123a, C. Da Via81, W. Dabrowski37, A. Dafinca117, T. Dai 86, C. Dallapiccola 83, M. Dam35, M. Dameri49a,49b, D.S. Damiani136, H.O. Danielsson29, V. Dao48, G. Darbo49a, G.L. Darlea25b, J.A. Dassoulas 41, W. Davey20, T. Davidek 125, N. Davidson 85, R. Davidson 70,E. Davies 117,c, M. Davies 92, O. Davignon 77, A.R. Davison 76, Y. Davygora57a, E. Dawe141, I. Dawson 138,R.K. Daya-Ishmukhametova22, K. De7, R. de Asmundis101a, S. De Castro19a,19b, S. De Cecco 77, J. de Graat 97, N. De Groot103, P. de Jong104, C. De La Taille 114, H. De la Torre79, F. De Lorenzi62, L. de Mora 70, L. De Nooij 104, D. De Pedis131a, A. De Salvo131a, U. De Sanctis163a,163c, A. De Santo148, J.B. De Vivie De Regie 114, G. De Zorzi131a,131b, W.J. Dearnaley 70, R. Debbe24, C. Debenedetti 45,B. Dechenaux 54, D.V. Dedovich 63, J. Degenhardt119, C. Del Papa163a,163c, J. Del Peso79, T. Del Prete 121a,121b, T. Delemontex 54, M. Deliyergiyev 73, A. Dell'Acqua 29, L. Dell'Asta 21,M. Della Pietra 101a,j, D. della Volpe 101a,101b, M. Delmastro4, P.A. Delsart54, C. Deluca 104, S. Demers 175, M. Demichev 63, B. Demirkoz 11,l, J. Deng162, S.P. Denisov127, D. Derendarz 38, J.E. Derkaoui 134d,F. Derue 77, P. Dervan72, K. Desch20, E. Devetak147, P.O. Deviveiros104, A. Dewhurst 128, B. DeWilde147,S. Dhaliwal 157, R. Dhullipudi 24,m, A. Di Ciaccio 132a,132b, L. Di Ciaccio 4, A. Di Girolamo 29,

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 41

B. Di Girolamo 29, S. Di Luise133a,133b, A. Di Mattia 172, B. Di Micco29, R. Di Nardo46,A. Di Simone 132a,132b, R. Di Sipio 19a,19b, M.A. Diaz 31a, E.B. Diehl 86, J. Dietrich 41, T.A. Dietzsch 57a, S. Diglio85, K. Dindar Yagci39, J. Dingfelder20, F. Dinut25a, C. Dionisi131a,131b, P. Dita 25a, S. Dita 25a, F. Dittus29, F. Djama82, T. Djobava50b, M.A.B. do Vale 23c, A. Do Valle Wemans 123a,n, T.K.O. Doan 4, M. Dobbs 84, R. Dobinson 29,∗, D. Dobos 29, E. Dobson 29,o, J. Dodd 34, C. Doglioni 48, T. Doherty 52, Y. Doi 64,∗, J. Dolejsi 125, I. Dolenc 73, Z. Dolezal 125, B.A. Dolgoshein 95,∗, T. Dohmae 154, M. Donadelli 23d, J. Donini 33, J. Dopke 29, A. Doria 101a, A. Dos Anjos 172, A. Dotti121a,121b, M.T. Dova69, A.D. Doxiadis 104,A.T. Doyle 52, N. Dressnandt119, M. Dris9, J. Dubbert98, S. Dube14, E. Duchovni171, G. Duckeck97,D. Duda174, A. Dudarev29, F. Dudziak62, M. Dührssen 29, I.P. Duerdoth81, L. Duflot114, M.-A. Dufour84, L. Duguid75, M. Dunford29, H. Duran Yildiz3a, R. Duxfield138, M. Dwuznik37, F. Dydak29, M. Düren51, W.L. Ebenstein44,J.Ebke97,S.Eckweiler80, K. Edmonds 80, W. Edson 1, C.A. Edwards 75, N.C. Edwards 52, W. Ehrenfeld41, T. Eifert142, G. Eigen13, K. Einsweiler 14, E. Eisenhandler74, T. Ekelof165, M. El Kacimi 134c, M. Ellert 165, S. Elles 4, F. Ellinghaus 80, K. Ellis 74, N. Ellis 29, J. Elmsheuser 97,M. Elsing 29, D. Emeliyanov 128, R. Engelmann147, A. Engl97, B. Epp60, J. Erdmann53, A. Ereditato16,D. Eriksson 145a, J. Ernst 1, M. Ernst24, J. Ernwein135, D. Errede164, S. Errede164, E. Ertel80, M. Escalier114, H. Esch42, C. Escobar122, X. Espinal Curull11, B. Esposito 46, F. Etienne 82, A.I. Etienvre 135,E. Etzion152, D. Evangelakou53, H. Evans59, L. Fabbri19a,19b, C. Fabre29, R.M. Fakhrutdinov 127, S. Falciano131a, Y. Fang172, M. Fanti88a,88b, A. Farbin7, A. Farilla133a, J. Farley147, T. Farooque 157, S. Farrell162, S.M. Farrington 169, P. Farthouat 29, F. Fassi 166, P. Fassnacht 29, D. Fassouliotis 8,B. Fatholahzadeh157, A. Favareto88a,88b, L. Fayard114, S. Fazio36a,36b, R. Febbraro33, P. Federic143a,O.L. Fedin120, W. Fedorko87, M. Fehling-Kaschek 47, L. Feligioni 82, D. Fellmann5, C. Feng32d, E.J. Feng 5,A.B. Fenyuk 127, J. Ferencei 143b, W. Fernando5, S. Ferrag52, J. Ferrando52, V. Ferrara41, A. Ferrari165,P. Ferrari 104, R. Ferrari118a, D.E. Ferreira de Lima52, A. Ferrer166, D. Ferrere48, C. Ferretti86,A. Ferretto Parodi 49a,49b, M. Fiascaris30, F. Fiedler80, A. Filipcˇicˇ 73, F. Filthaut 103, M. Fincke-Keeler 168, M.C.N. Fiolhais 123a,h, L. Fiorini166, A. Firan39, G. Fischer41, M.J. Fisher108, M. Flechl47, I. Fleck140, J. Fleckner80, P. Fleischmann173, S. Fleischmann174, T. Flick174, A. Floderus78, L.R. Flores Castillo 172, M.J. Flowerdew 98, T. Fonseca Martin16, A. Formica135, A. Forti81, D. Fortin158a, D. Fournier 114,A.J. Fowler44, H. Fox70, P. Francavilla 11, M. Franchini 19a,19b, S. Franchino118a,118b, D. Francis29,T. Frank 171, S. Franz29, M. Fraternali118a,118b, S. Fratina119, S.T. French27, C. Friedrich 41, F. Friedrich 43,R. Froeschl 29, D. Froidevaux29, J.A. Frost27, C. Fukunaga 155, E. Fullana Torregrosa29, B.G. Fulsom 142, J. Fuster 166, C. Gabaldon29, O. Gabizon171, A. Gabrielli 131a,131b, T. Gadfort24, S. Gadomski 48,G. Gagliardi49a,49b, P. Gagnon59, C. Galea97, B. Galhardo123a, E.J. Gallas 117, V. Gallo 16, B.J. Gallop 128, P. Gallus124, K.K. Gan108, Y.S. Gao142,e, A. Gaponenko14, F. Garberson 175, M. Garcia-Sciveres 14,C. García 166, J.E. García Navarro166, R.W. Gardner30, N. Garelli 29, H. Garitaonandia 104, V. Garonne 29,C. Gatti 46, G. Gaudio118a, B. Gaur140, L. Gauthier 135, P. Gauzzi 131a,131b, I.L. Gavrilenko93, C. Gay167, G. Gaycken 20, E.N. Gazis9, P. Ge32d, Z. Gecse167, C.N.P. Gee 128, D.A.A. Geerts 104, Ch. Geich-Gimbel 20,K. Gellerstedt 145a,145b, C. Gemme 49a, A. Gemmell 52, M.H. Genest54,S.Gentile131a,131b,M.George53,S. George75, P. Gerlach174, A. Gershon 152, C. Geweniger57a,H.Ghazlane134b,N.Ghodbane33,B. Giacobbe19a, S. Giagu 131a,131b, V. Giakoumopoulou 8, V. Giangiobbe 11, F. Gianotti 29, B. Gibbard 24,A. Gibson 157, S.M. Gibson 29, M. Gilchriese 14, D. Gillberg28, A.R. Gillman 128, D.M. Gingrich 2,d, J. Ginzburg 152, N. Giokaris 8, M.P. Giordani 163c, R. Giordano 101a,101b, F.M. Giorgi 15, P. Giovannini 98, P.F. Giraud135, D. Giugni 88a, M. Giunta 92, P. Giusti19a, B.K. Gjelsten116, L.K. Gladilin96, C. Glasman79, J. Glatzer47, A. Glazov41, K.W. Glitza174, G.L. Glonti63, J.R. Goddard74, J. Godfrey141, J. Godlewski29, M. Goebel41, T. Göpfert43, C. Goeringer 80, C. Gössling42, S. Goldfarb86, T. Golling175, A. Gomes123a,b,L.S. Gomez Fajardo41, R. Gonçalo75, J. Goncalves Pinto Firmino Da Costa 41, L. Gonella 20, S. Gonzalez172, S. González de la Hoz166, G. Gonzalez Parra11, M.L. Gonzalez Silva26, S. Gonzalez-Sevilla 48, J.J. Goodson 147, L. Goossens29, P.A. Gorbounov94, H.A. Gordon24, I. Gorelov102, G. Gorfine174,B. Gorini 29, E. Gorini 71a,71b, A. Gorišek 73, E. Gornicki 38, B. Gosdzik 41, A.T. Goshaw 5, M. Gosselink 104,M.I. Gostkin 63, I. Gough Eschrich 162, M. Gouighri134a, D. Goujdami134c, M.P. Goulette48,A.G. Goussiou137, C. Goy4, S. Gozpinar22, I. Grabowska-Bold37, P. Grafström19a,19b, K.-J. Grahn 41,F. Grancagnolo 71a, S. Grancagnolo 15, V. Grassi147, V. Gratchev120, N. Grau34, H.M. Gray29, J.A. Gray147,E. Graziani133a, O.G. Grebenyuk120, T. Greenshaw 72, Z.D. Greenwood24,m, K. Gregersen35, I.M. Gregor 41,

42 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

P. Grenier 142, J. Griffiths 7, N. Grigalashvili 63, A.A. Grillo 136, S. Grinstein11, Ph. Gris33,Y.V. Grishkevich96, J.-F. Grivaz114, E. Gross 171, J. Grosse-Knetter53, J. Groth-Jensen171, K. Grybel140,D. Guest 175, C. Guicheney33, S. Guindon53, U. Gul52, H. Guler 84,p, J. Gunther124, B. Guo157, J. Guo34, P. Gutierrez110, N. Guttman 152, O. Gutzwiller172,C.Guyot135,C.Gwenlan117, C.B. Gwilliam 72,A. Haas 142, S. Haas29, C. Haber14, H.K. Hadavand39, D.R. Hadley17, P. Haefner20, F. Hahn29, S. Haider29, Z. Hajduk38, H. Hakobyan176, D. Hall117, J. Haller 53, K. Hamacher 174, P. Hamal 112, K. Hamano 85, M. Hamer 53, A. Hamilton 144b,q, S. Hamilton160, L. Han32b, K. Hanagaki115, K. Hanawa159, M. Hance14,C. Handel80, P. Hanke57a, J.R. Hansen35, J.B. Hansen35, J.D. Hansen35, P.H. Hansen35, P. Hansson 142,K. Hara 159, G.A. Hare136, T. Harenberg174, S. Harkusha89, D. Harper86, R.D. Harrington 45,O.M. Harris137, J. Hartert47, F. Hartjes104, T. Haruyama64, A. Harvey55, S. Hasegawa100, Y. Hasegawa139, S. Hassani135, S. Haug16, M. Hauschild29, R. Hauser87, M. Havranek20, C.M. Hawkes17, R.J. Hawkings29,A.D. Hawkins78, D. Hawkins162, T. Hayakawa65, T. Hayashi159, D. Hayden75, C.P. Hays117,H.S. Hayward 72, S.J. Haywood128, M. He32d, S.J. Head17, V. Hedberg78, L. Heelan7, S. Heim87,B. Heinemann 14, S. Heisterkamp35, L. Helary21, C. Heller 97, M. Heller 29, S. Hellman 145a,145b,D. Hellmich20, C. Helsens11, R.C.W. Henderson70, M. Henke57a, A. Henrichs 53,A.M. Henriques Correia29, S. Henrot-Versille114, C. Hensel53, T. Henß174, C.M. Hernandez 7,Y. Hernández Jiménez 166, R. Herrberg15, G. Herten47, R. Hertenberger97, L. Hervas29, G.G. Hesketh76,N.P. Hessey 104, E. Higón-Rodriguez 166, J.C. Hill 27, K.H. Hiller 41, S. Hillert 20, S.J. Hillier 17, I. Hinchliffe 14,E. Hines 119, M. Hirose 115, F. Hirsch 42, D. Hirschbuehl 174, J. Hobbs147, N. Hod152, M.C. Hodgkinson 138,P. Hodgson138, A. Hoecker29, M.R. Hoeferkamp102, J. Hoffman39, D. Hoffmann82, M. Hohlfeld80, M. Holder 140, S.O. Holmgren 145a, T. Holy126, J.L. Holzbauer87, T.M. Hong119,L. Hooft van Huysduynen 107, S. Horner47, J.-Y. Hostachy54, S. Hou150, A. Hoummada134a, J. Howard117, J. Howarth81, I. Hristova15, J. Hrivnac114, T. Hryn'ova4, P.J. Hsu80, S.-C. Hsu14, D. Hu34, Z. Hubacek 126,F. Hubaut 82, F. Huegging 20, A. Huettmann41, T.B. Huffman117, E.W. Hughes34, G. Hughes70,M. Huhtinen 29, M. Hurwitz 14, U. Husemann 41, N. Huseynov63,r, J. Huston87, J. Huth56, G. Iacobucci 48,G. Iakovidis 9, M. Ibbotson 81, I. Ibragimov140, L. Iconomidou-Fayard114, J. Idarraga114, P. Iengo101a,O. Igonkina104, Y. Ikegami64, M. Ikeno64, D. Iliadis153, N. Ilic157, T. Ince20, J. Inigo-Golfin 29,P. Ioannou 8, M. Iodice 133a, K. Iordanidou 8, V. Ippolito 131a,131b, A. Irles Quiles 166, C. Isaksson165, M. Ishino 66, M. Ishitsuka156, R. Ishmukhametov39, C. Issever117, S. Istin18a, A.V. Ivashin127, W. Iwanski 38, H. Iwasaki64, J.M. Izen40, V. Izzo 101a, B. Jackson119, J.N. Jackson 72, P. Jackson142, M.R. Jaekel29, V. Jain59, K. Jakobs47, S. Jakobsen35, T. Jakoubek124, J. Jakubek126, D.K. Jana110,E. Jansen76, H. Jansen29, A. Jantsch98, M. Janus47, G. Jarlskog78, L. Jeanty56, I. Jen-La Plante30,D. Jennens 85, P. Jenni 29, A.E. Loevschall-Jensen35, P. Jež35, S. Jézéquel4, M.K. Jha19a, H. Ji172, W. Ji80, J. Jia147, Y. Jiang32b, M. Jimenez Belenguer41, S. Jin32a, O. Jinnouchi 156, M.D. Joergensen35, D. Joffe39, M. Johansen 145a,145b, K.E. Johansson 145a, P. Johansson 138, S. Johnert 41, K.A. Johns6, K. Jon-And145a,145b,G. Jones 169, R.W.L. Jones70, T.J. Jones72, C. Joram29, P.M. Jorge123a, K.D. Joshi 81, J. Jovicevic 146,T. Jovin 12b, X. Ju172, C.A. Jung42, R.M. Jungst 29, V. Juranek 124, P. Jussel60, A. Juste Rozas11, S. Kabana 16, M. Kaci 166, A. Kaczmarska38, P. Kadlecik35, M. Kado114, H. Kagan 108, M. Kagan 56, E. Kajomovitz 151, S. Kalinin 174, L.V. Kalinovskaya63, S. Kama39, N. Kanaya154, M. Kaneda29, S. Kaneti27, T. Kanno 156, V.A. Kantserov95, J. Kanzaki64, B. Kaplan107, A. Kapliy30, J. Kaplon29, D. Kar52, M. Karagounis 20,K. Karakostas 9, M. Karnevskiy 41, V. Kartvelishvili70, A.N. Karyukhin127, L. Kashif172, G. Kasieczka57b, R.D. Kass108, A. Kastanas13, M. Kataoka 4, Y. Kataoka 154, E. Katsoufis9, J. Katzy41, V. Kaushik6,K. Kawagoe68, T. Kawamoto154, G. Kawamura80, M.S. Kayl104, S. Kazama 154, V.A. Kazanin 106, M.Y. Kazarinov 63, R. Keeler 168, P.T. Keener119, R. Kehoe39, M. Keil53, G.D. Kekelidze 63, J.S. Keller 137, M. Kenyon52, O. Kepka124, N. Kerschen29, B.P. Kerševan 73, S. Kersten 174, K. Kessoku 154, J. Keung 157,F. Khalil-zada 10, H. Khandanyan145a,145b, A. Khanov 111, D. Kharchenko 63, A. Khodinov 95,A. Khomich57a, T.J. Khoo27, G. Khoriauli 20, A. Khoroshilov 174, V. Khovanskiy94, E. Khramov63, J. Khubua50b, H. Kim145a,145b, S.H. Kim159, N. Kimura 170, O. Kind 15, B.T. King 72, M. King 65, R.S.B. King 117, J. Kirk 128, A.E. Kiryunin98, T. Kishimoto65, D. Kisielewska 37, T. Kitamura 65, T. Kittelmann122, K. Kiuchi159, E. Kladiva143b, M. Klein72, U. Klein72, K. Kleinknecht80, M. Klemetti 84, A. Klier171, P. Klimek145a,145b, A. Klimentov24, R. Klingenberg42, J.A. Klinger81, E.B. Klinkby 35, T. Klioutchnikova29, P.F. Klok103, S. Klous104, E.-E. Kluge57a, T. Kluge72, P. Kluit104, S. Kluth98,

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 43

N.S. Knecht 157, E. Kneringer 60, E.B.F.G. Knoops 82, A. Knue53, B.R. Ko44, T. Kobayashi154, M. Kobel43, M. Kocian 142, P. Kodys125, K. Köneke29, A.C. König103, S. Koenig80, L. Köpke80, F. Koetsveld103, P. Koevesarki 20, T. Koffas28, E. Koffeman104, L.A. Kogan117, S. Kohlmann174, F. Kohn53, Z. Kohout 126, T. Kohriki 64, T. Koi142, G.M. Kolachev106,∗, H. Kolanoski15, V. Kolesnikov63, I. Koletsou 88a,J.Koll87, M. Kollefrath 47, A.A. Komar93, Y. Komori 154, T. Kondo64, T. Kono41,s, A.I. Kononov 47, R. Konoplich 107,t ,N. Konstantinidis 76, S. Koperny37, K. Korcyl38, K. Kordas153, A. Korn117, A. Korol 106, I. Korolkov 11,E.V. Korolkova138, V.A. Korotkov127, O. Kortner98, S. Kortner98, V.V. Kostyukhin20, S. Kotov98, V.M. Kotov63, A. Kotwal44, C. Kourkoumelis 8, V. Kouskoura 153, A. Koutsman158a, R. Kowalewski168, T.Z. Kowalski 37, W. Kozanecki 135, A.S. Kozhin127, V. Kral126, V.A. Kramarenko 96, G. Kramberger73, M.W. Krasny 77, A. Krasznahorkay 107, J.K. Kraus20, S. Kreiss 107, F. Krejci126, J. Kretzschmar72, N. Krieger 53, P. Krieger 157, K. Kroeninger53, H. Kroha98, J. Kroll119, J. Kroseberg20, J. Krstic12a,U. Kruchonak63, H. Krüger20, T. Kruker16, N. Krumnack62, Z.V. Krumshteyn63, T. Kubota85, S. Kuday3a, S. Kuehn 47, A. Kugel57c, T. Kuhl41, D. Kuhn60, V. Kukhtin63, Y. Kulchitsky 89, S. Kuleshov 31b,C. Kummer97, M. Kuna77, J. Kunkle119, A. Kupco124, H. Kurashige65, M. Kurata159, Y.A. Kurochkin89,V. Kus 124, E.S. Kuwertz146, M. Kuze156, J. Kvita141, R. Kwee15, A. La Rosa48, L. La Rotonda36a,36b,L. Labarga79,J.Labbe4,S.Lablak134a, C. Lacasta 166, F. Lacava131a,131b, H. Lacker15, D. Lacour77, V.R. Lacuesta 166, E. Ladygin 63, R. Lafaye4, B. Laforge77, T. Lagouri79, S. Lai47, E. Laisne54,M. Lamanna 29, L. Lambourne 76, C.L. Lampen6, W. Lampl6, E. Lancon135, U. Landgraf47, M.P.J. Landon 74, J.L. Lane 81, V.S. Lang57a, C. Lange41, A.J. Lankford162, F. Lanni 24, K. Lantzsch174, S. Laplace77,C. Lapoire 20, J.F. Laporte135, T. Lari88a, A. Larner 117, M. Lassnig 29, P. Laurelli 46, V. Lavorini 36a,36b,W. Lavrijsen 14, P. Laycock72, O. Le Dortz 77, E. Le Guirriec 82, C. Le Maner157, E. Le Menedeu 11,T. LeCompte 5, F. Ledroit-Guillon 54, H. Lee104, J.S.H. Lee115, S.C. Lee150, L. Lee175, M. Lefebvre 168, M. Legendre135, F. Legger97, C. Leggett14, M. Lehmacher 20, G. Lehmann Miotto 29,X.Lei6, M.A.L. Leite 23d, R. Leitner 125, D. Lellouch 171, B. Lemmer 53, V. Lendermann57a, K.J.C. Leney 144b, T. Lenz 104, G. Lenzen174, B. Lenzi29, K. Leonhardt 43, S. Leontsinis9, F. Lepold57a, C. Leroy92, J.-R. Lessard 168, C.G. Lester27, C.M. Lester119, J. Levêque 4, D. Levin 86, L.J. Levinson 171, A. Lewis 117,G.H. Lewis 107, A.M. Leyko20, M. Leyton15, B. Li82, H. Li172,u, S. Li32b,v, X. Li86, Z. Liang117,w, H. Liao 33,B. Liberti 132a, P. Lichard29, M. Lichtnecker 97,K.Lie164, W. Liebig13, C. Limbach20, A. Limosani 85, M. Limper 61, S.C. Lin150,x, F. Linde104, J.T. Linnemann 87, E. Lipeles 119, A. Lipniacka13, T.M. Liss 164,D. Lissauer 24, A. Lister 48, A.M. Litke136, C. Liu28, D. Liu150, H. Liu86, J.B. Liu86, L. Liu86, M. Liu32b, Y. Liu 32b, M. Livan118a,118b, S.S.A. Livermore117, A. Lleres54, J. Llorente Merino79, S.L. Lloyd74,E. Lobodzinska41, P. Loch6, W.S. Lockman136, T. Loddenkoetter 20, F.K. Loebinger81, A. Loginov 175,C.W. Loh 167, T. Lohse 15, K. Lohwasser 47, M. Lokajicek124, V.P. Lombardo4, R.E. Long 70, L. Lopes123a,D. Lopez Mateos 56, J. Lorenz97, N. Lorenzo Martinez 114, M. Losada 161, P. Loscutoff 14,F. Lo Sterzo131a,131b, M.J. Losty158a,∗, X. Lou40, A. Lounis114, K.F. Loureiro 161,J.Love5,P.A.Love70, A.J. Lowe142,e, F. Lu32a, H.J. Lubatti137, C. Luci131a,131b, A. Lucotte54, A. Ludwig 43, D. Ludwig 41,I. Ludwig 47, J. Ludwig 47, F. Luehring59, G. Luijckx104, W. Lukas60, D. Lumb47, L. Luminari 131a,E. Lund 116, B. Lund-Jensen 146, B. Lundberg 78, J. Lundberg 145a,145b, O. Lundberg145a,145b, J. Lundquist 35, M. Lungwitz 80, D. Lynn 24, E. Lytken78, H. Ma24, L.L. Ma172, G. Maccarrone 46, A. Macchiolo98,B. Macˇek 73, J. Machado Miguens 123a, R. Mackeprang 35, R.J. Madaras 14, H.J. Maddocks 70, W.F. Mader43, R. Maenner57c, T. Maeno24, P. Mättig 174, S. Mättig 80, L. Magnoni162, E. Magradze53, K. Mahboubi47, S. Mahmoud72, G. Mahout17, C. Maiani 135, C. Maidantchik23a, A. Maio123a,b, S. Majewski24, Y. Makida 64,N.Makovec114,P.Mal135, B. Malaescu 29, Pa. Malecki 38, P. Malecki38, V.P. Maleev120,F. Malek 54, U. Mallik 61, D. Malon5, C. Malone142, S. Maltezos9, V. Malyshev106, S. Malyukov29, R. Mameghani 97, J. Mamuzic12b, A. Manabe64, L. Mandelli88a, I. Mandic´ 73, R. Mandrysch15,J. Maneira 123a, A. Manfredini 98, P.S. Mangeard 87, L. Manhaes de Andrade Filho 23b,J.A. Manjarres Ramos135, A. Mann53, P.M. Manning 136, A. Manousakis-Katsikakis 8, B. Mansoulie 135, A. Mapelli 29, L. Mapelli 29, L. March79, J.F. Marchand28, F. Marchese132a,132b, G. Marchiori77, M. Marcisovsky 124, C.P. Marino 168, F. Marroquim23a, Z. Marshall 29, F.K. Martens157, L.F. Marti16, S. Marti-Garcia 166, B. Martin29, B. Martin87, J.P. Martin92, T.A. Martin17, V.J. Martin45,B. Martin dit Latour 48, S. Martin-Haugh148, M. Martinez11, V. Martinez Outschoorn 56, A.C. Martyniuk168, M. Marx81, F. Marzano131a, A. Marzin110, L. Masetti80, T. Mashimo154,

44 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

R. Mashinistov 93, J. Masik81, A.L. Maslennikov 106, I. Massa 19a,19b, G. Massaro 104, N. Massol 4, P. Mastrandrea 147, A. Mastroberardino 36a,36b, T. Masubuchi154, P. Matricon114, H. Matsunaga154,T. Matsushita 65, C. Mattravers 117,c,J.Maurer82,S.J.Maxfield72, A. Mayne 138, R. Mazini150, M. Mazur20,L. Mazzaferro 132a,132b, M. Mazzanti 88a, J. Mc Donald84, S.P. Mc Kee86, A. McCarn164, R.L. McCarthy147, T.G. McCarthy 28, N.A. McCubbin 128, K.W. McFarlane55,∗, J.A. Mcfayden138, G. Mchedlidze50b,T. Mclaughlan 17, S.J. McMahon128, R.A. McPherson168,k, A. Meade83, J. Mechnich 104, M. Mechtel 174,M. Medinnis 41, R. Meera-Lebbai 110, T. Meguro 115, R. Mehdiyev92, S. Mehlhase35, A. Mehta72,K. Meier 57a, B. Meirose 78, C. Melachrinos 30, B.R. Mellado Garcia 172, F. Meloni88a,88b,L. Mendoza Navas 161, Z. Meng150,u, A. Mengarelli 19a,19b, S. Menke98, E. Meoni160, K.M. Mercurio56,P. Mermod 48, L. Merola101a,101b, C. Meroni88a, F.S. Merritt30, H. Merritt108, A. Messina 29,y,J. Metcalfe 24,A.S.Mete162,C.Meyer80,C.Meyer30, J.-P. Meyer 135,J.Meyer173,J.Meyer53,T.C.Meyer29, J. Miao 32d, S. Michal 29, L. Micu 25a, R.P. Middleton 128, S. Migas 72, L. Mijovic´ 135, G. Mikenberg 171,M. Mikestikova 124, M. Mikuž 73, D.W. Miller 30, R.J. Miller 87, W.J. Mills 167, C. Mills 56, A. Milov 171,D.A. Milstead 145a,145b, D. Milstein 171, A.A. Minaenko 127, M. Miñano Moya 166, I.A. Minashvili 63, A.I. Mincer 107, B. Mindur 37, M. Mineev 63, Y. Ming 172, L.M. Mir 11, G. Mirabelli 131a, J. Mitrevski 136, V.A. Mitsou 166, S. Mitsui 64, P.S. Miyagawa 138, J.U. Mjörnmark 78, T. Moa145a,145b, V. Moeller 27,K. Mönig 41, N. Möser 20, S. Mohapatra147, W. Mohr47, R. Moles-Valls166, A. Molfetas29, J. Monk76,E. Monnier 82, J. Montejo Berlingen 11, F. Monticelli 69, S. Monzani19a,19b, R.W. Moore 2, G.F. Moorhead 85,C. Mora Herrera48, A. Moraes52, N. Morange135, J. Morel53, G. Morello 36a,36b, D. Moreno80,M. Moreno Llácer 166, P. Morettini 49a, M. Morgenstern 43, M. Morii56, A.K. Morley29, G. Mornacchi 29, J.D. Morris74, L. Morvaj100, H.G. Moser 98, M. Mosidze 50b, J. Moss 108, R. Mount142, E. Mountricha 9,z, S.V. Mouraviev 93,∗, E.J.W. Moyse 83, F. Mueller 57a, J. Mueller 122, K. Mueller 20, T.A. Müller 97, T. Mueller 80, D. Muenstermann29, Y. Munwes152, W.J. Murray128, I. Mussche 104, E. Musto101a,101b, A.G. Myagkov 127, M. Myska124, J. Nadal 11, K. Nagai 159, R. Nagai 156, K. Nagano 64, A. Nagarkar 108, Y. Nagasaka 58, M. Nagel98, A.M. Nairz29, Y. Nakahama 29, K. Nakamura 154, T. Nakamura 154,I. Nakano109, G. Nanava20, A. Napier 160, R. Narayan 57b, M. Nash76,c, T. Nattermann 20, T. Naumann41,G. Navarro 161, H.A. Neal86, P.Yu. Nechaeva93, T.J. Neep 81, A. Negri118a,118b, G. Negri29, M. Negrini 19a, S. Nektarijevic 48, A. Nelson 162, T.K. Nelson 142, S. Nemecek 124, P. Nemethy107, A.A. Nepomuceno 23a, M. Nessi 29,aa, M.S. Neubauer 164, M. Neumann 174, A. Neusiedl 80,R.M.Neves107,P.Nevski24,F.M. Newcomer 119, P.R. Newman 17, V. Nguyen Thi Hong 135, R.B. Nickerson 117, R. Nicolaidou 135,B. Nicquevert 29, F. Niedercorn 114, J. Nielsen136, N. Nikiforou 34, A. Nikiforov 15, V. Nikolaenko 127, I. Nikolic-Audit 77, K. Nikolics 48, K. Nikolopoulos 17, H. Nilsen 47, P. Nilsson 7, Y. Ninomiya 154, A. Nisati 131a, R. Nisius 98, T. Nobe156, L. Nodulman5, M. Nomachi115, I. Nomidis 153, S. Norberg110, M. Nordberg 29, P.R. Norton128, J. Novakova 125, M. Nozaki64, L. Nozka112, I.M. Nugent 158a, A.-E. Nuncio-Quiroz 20, G. Nunes Hanninger 85, T. Nunnemann 97, E. Nurse76, B.J. O'Brien45, S.W. O'Neale 17,∗, D.C. O'Neil141, V. O'Shea52, L.B. Oakes97, F.G. Oakham28,d, H. Oberlack98, J. Ocariz 77, A. Ochi65, S. Oda68, S. Odaka64, J. Odier82, H. Ogren59, A. Oh81, S.H. Oh44, C.C. Ohm29, T. Ohshima 100,H. Okawa 24, Y. Okumura30, T. Okuyama154, A. Olariu25a, A.G. Olchevski63, S.A. Olivares Pino 31a, M. Oliveira 123a,h, D. Oliveira Damazio 24, E. Oliver Garcia166, D. Olivito 119, A. Olszewski38,J. Olszowska 38, A. Onofre123a,ab, P.U.E. Onyisi 30, C.J. Oram158a, M.J. Oreglia30, Y. Oren152,D. Orestano 133a,133b, N. Orlando71a,71b, I. Orlov106, C. Oropeza Barrera52, R.S. Orr157, B. Osculati49a,49b, R. Ospanov 119, C. Osuna11, G. Otero y Garzon26, J.P. Ottersbach104, M. Ouchrif 134d, E.A. Ouellette 168,F. Ould-Saada 116, A. Ouraou135, Q. Ouyang32a, A. Ovcharova14, M. Owen81, S. Owen138, V.E. Ozcan 18a,N. Ozturk 7, A. Pacheco Pages11, C. Padilla Aranda 11, S. Pagan Griso 14, E. Paganis138, C. Pahl98,F. Paige 24, P. Pais83, K. Pajchel116, G. Palacino 158b,C.P.Paleari6,S.Palestini29, D. Pallin 33, A. Palma123a, J.D. Palmer 17, Y.B. Pan172, E. Panagiotopoulou9, P. Pani104, N. Panikashvili 86, S. Panitkin 24, D. Pantea25a, A. Papadelis 145a, Th.D. Papadopoulou 9, A. Paramonov 5, D. Paredes Hernandez33, W. Park24,ac, M.A. Parker 27, F. Parodi49a,49b, J.A. Parsons 34, U. Parzefall47, S. Pashapour53, E. Pasqualucci 131a, S. Passaggio 49a, A. Passeri133a, F. Pastore133a,133b,∗, Fr. Pastore75, G. Pásztor48,ad, S. Pataraia 174,N. Patel 149, J.R. Pater81, S. Patricelli 101a,101b, T. Pauly 29, M. Pecsy143a, S. Pedraza Lopez 166,M.I. Pedraza Morales 172, S.V. Peleganchuk106, D. Pelikan165, H. Peng32b, B. Penning 30, A. Penson 34, J. Penwell59, M. Perantoni23a, K. Perez 34,ae, T. Perez Cavalcanti 41, E. Perez Codina 158a,

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 45

M.T. Pérez García-Estañ 166, V. Perez Reale 34, L. Perini 88a,88b, H. Pernegger 29, R. Perrino71a, P. Perrodo4, V.D. Peshekhonov63, K. Peters29, B.A. Petersen29, J. Petersen29, T.C. Petersen35, E. Petit4, A. Petridis153,C. Petridou153, E. Petrolo131a, F. Petrucci133a,133b, D. Petschull41, M. Petteni141, R. Pezoa31b, A. Phan85, P.W. Phillips 128, G. Piacquadio 29, A. Picazio 48, E. Piccaro 74, M. Piccinini 19a,19b, S.M. Piec 41, R. Piegaia 26,D.T. Pignotti 108, J.E. Pilcher 30, A.D. Pilkington 81, J. Pina123a,b, M. Pinamonti163a,163c, A. Pinder 117, J.L. Pinfold2, B. Pinto123a, C. Pizio88a,88b, M. Plamondon168, M.-A. Pleier 24, E. Plotnikova 63, A. Poblaguev 24, S. Poddar 57a, F. Podlyski 33, L. Poggioli 114, D. Pohl20, M. Pohl48, G. Polesello 118a, A. Policicchio 36a,36b, A. Polini19a, J. Poll74, V. Polychronakos24, D. Pomeroy22, K. Pommès 29,L. Pontecorvo131a, B.G. Pope87, G.A. Popeneciu 25a, D.S. Popovic 12a, A. Poppleton 29, X. Portell Bueso 29,G.E. Pospelov 98, S. Pospisil 126, I.N. Potrap98, C.J. Potter148, C.T. Potter113, G. Poulard29, J. Poveda59, V. Pozdnyakov63, R. Prabhu76, P. Pralavorio82, A. Pranko14, S. Prasad29, R. Pravahan24, S. Prell62,K. Pretzl16, D. Price59, J. Price72, L.E. Price 5, D. Prieur122, M. Primavera71a, K. Prokofiev107, F. Prokoshin 31b, S. Protopopescu24, J. Proudfoot5, X. Prudent 43, M. Przybycien 37, H. Przysiezniak4, S. Psoroulas20, E. Ptacek113, E. Pueschel83, J. Purdham86, M. Purohit24,ac, P. Puzo114, Y. Pylypchenko61, J. Qian86, A. Quadt53, D.R. Quarrie14, W.B. Quayle172, F. Quinonez 31a, M. Raas103, V. Radeka24, V. Radescu41, P. Radloff113, T. Rador18a, F. Ragusa88a,88b, G. Rahal177, A.M. Rahimi108, D. Rahm24, S. Rajagopalan 24, M. Rammensee47, M. Rammes140, A.S. Randle-Conde39, K. Randrianarivony 28, F. Rauscher97, T.C. Rave47, M. Raymond29, A.L. Read116, D.M. Rebuzzi118a,118b, A. Redelbach173,G. Redlinger24, R. Reece119, K. Reeves40, E. Reinherz-Aronis152, A. Reinsch113, I. Reisinger 42,C. Rembser29, Z.L. Ren150, A. Renaud114, M. Rescigno131a, S. Resconi88a, B. Resende135, P. Reznicek97, R. Rezvani157, R. Richter98, E. Richter-Was4,af, M. Ridel77, M. Rijpstra 104, M. Rijssenbeek 147, A. Rimoldi118a,118b, L. Rinaldi19a, R.R. Rios39, I. Riu11, G. Rivoltella88a,88b, F. Rizatdinova111, E. Rizvi 74, S.H. Robertson 84,k, A. Robichaud-Veronneau 117, D. Robinson 27, J.E.M. Robinson 81, A. Robson 52, J.G. Rocha de Lima 105, C. Roda121a,121b, D. Roda Dos Santos29, A. Roe53, S. Roe29, O. Røhne 116, S. Rolli160, A. Romaniouk95, M. Romano19a,19b, G. Romeo26, E. Romero Adam166, N. Rompotis 137,L. Roos77, E. Ros166, S. Rosati 131a, K. Rosbach 48, A. Rose 148, M. Rose 75, G.A. Rosenbaum 157,E.I. Rosenberg 62, P.L. Rosendahl 13, O. Rosenthal 140, L. Rosselet 48, V. Rossetti 11, E. Rossi 131a,131b, L.P. Rossi49a, M. Rotaru25a, I. Roth171, J. Rothberg137, D. Rousseau114, C.R. Royon135, A. Rozanov82, Y. Rozen151,X.Ruan32a,ag, F. Rubbo 11, I. Rubinskiy41, N. Ruckstuhl104, V.I. Rud 96, J.T. Ruderman 137,ah,C. Rudolph43, G. Rudolph60, F. Rühr6, A. Ruiz-Martinez62, L. Rumyantsev63, Z. Rurikova 47,N.A. Rusakovich 63, J.P. Rutherfoord 6, C. Ruwiedel14,∗, P. Ruzicka124, Y.F. Ryabov120, M. Rybar125,G. Rybkin114, N.C. Ryder117, A.F. Saavedra149, I. Sadeh152, H.F.-W. Sadrozinski136, R. Sadykov63,F. Safai Tehrani 131a, H. Sakamoto 154, G. Salamanna 74, A. Salamon 132a, M. Saleem110, D. Salek29,D. Salihagic98, A. Salnikov142, J. Salt166, B.M. Salvachua Ferrando5, D. Salvatore36a,36b, F. Salvatore148, A. Salvucci103, A. Salzburger29, D. Sampsonidis153, B.H. Samset116, A. Sanchez101a,101b,V. Sanchez Martinez166, H. Sandaker13, H.G. Sander80, M.P. Sanders97, M. Sandhoff174, T. Sandoval27, C. Sandoval161, R. Sandstroem98, D.P.C. Sankey 128, A. Sansoni 46, C. Santamarina Rios84, C. Santoni33, R. Santonico132a,132b, H. Santos123a, J.G. Saraiva 123a, T. Sarangi 172, E. Sarkisyan-Grinbaum 7, F. Sarri121a,121b, G. Sartisohn 174, O. Sasaki 64, Y. Sasaki 154, N. Sasao 66, I. Satsounkevitch 89,G. Sauvage4,∗, E. Sauvan4, J.B. Sauvan114, P. Savard157,d, V. Savinov122, D.O. Savu29, L. Sawyer24,m,D.H. Saxon52, J. Saxon119, C. Sbarra19a, A. Sbrizzi 19a,19b, D.A. Scannicchio 162, M. Scarcella 149, J. Schaarschmidt114, P. Schacht98, D. Schaefer119, U. Schäfer80, S. Schaepe20, S. Schaetzel57b, A.C. Schaffer114, D. Schaile97, R.D. Schamberger147, A.G. Schamov106, V. Scharf57a, V.A. Schegelsky 120,D. Scheirich 86, M. Schernau 162, M.I. Scherzer 34, C. Schiavi49a,49b, J. Schieck97, M. Schioppa 36a,36b, S. Schlenker29, E. Schmidt47, K. Schmieden20, C. Schmitt80, S. Schmitt57b, M. Schmitz20,B. Schneider 16, U. Schnoor 43, A. Schoening 57b, A.L.S. Schorlemmer53,M.Schott29,D.Schouten158a, J. Schovancova124, M. Schram84, C. Schroeder80, N. Schroer57c, M.J. Schultens20, J. Schultes174,H.-C. Schultz-Coulon57a, H. Schulz15, M. Schumacher47, B.A. Schumm136, Ph. Schune 135,C. Schwanenberger81, A. Schwartzman142, Ph. Schwegler 98, Ph. Schwemling 77, R. Schwienhorst 87, R. Schwierz 43, J. Schwindling 135, T. Schwindt 20, M. Schwoerer 4, G. Sciolla22, W.G. Scott128, J. Searcy 113,G. Sedov41, E. Sedykh120, S.C. Seidel 102, A. Seiden 136, F. Seifert 43, J.M. Seixas 23a, G. Sekhniaidze 101a, S.J. Sekula 39, K.E. Selbach 45, D.M. Seliverstov 120, B. Sellden 145a, G. Sellers 72, M. Seman 143b,

46 ATLAS Collaboration / Physics Letters B 721 (2013) 32–50

N. Semprini-Cesari 19a,19b, C. Serfon 97, L. Serin 114, L. Serkin 53, R. Seuster 98, H. Severini110, A. Sfyrla29,E. Shabalina53, M. Shamim113, L.Y. Shan32a, J.T. Shank21, Q.T. Shao85, M. Shapiro14, P.B. Shatalov94,K. Shaw 163a,163c, D. Sherman 175, P. Sherwood76,A.Shibata107,S.Shimizu100, M. Shimojima 99,T. Shin 55, M. Shiyakova63, A. Shmeleva93, M.J. Shochet30, D. Short117, S. Shrestha62, E. Shulga95,M.A. Shupe6, P. Sicho124, A. Sidoti131a, F. Siegert47, Dj. Sijacki12a, O. Silbert171, J. Silva123a, Y. Silver 152,D. Silverstein 142, S.B. Silverstein145a, V. Simak126, O. Simard135, Lj. Simic12a, S. Simion 114, E. Simioni 80,B. Simmons 76, R. Simoniello 88a,88b, M. Simonyan35, P. Sinervo157, N.B. Sinev113, V. Sipica 140, G. Siragusa 173, A. Sircar 24, A.N. Sisakyan 63,∗, S.Yu. Sivoklokov96, J. Sjölin145a,145b, T.B. Sjursen 13,L.A. Skinnari14, H.P. Skottowe56, K. Skovpen106, P. Skubic110, M. Slater17, T. Slavicek126, K. Sliwa160, V. Smakhtin 171, B.H. Smart 45, S.Yu. Smirnov 95, Y. Smirnov 95, L.N. Smirnova 96, O. Smirnova 78,B.C. Smith56, D. Smith142, K.M. Smith52, M. Smizanska70, K. Smolek126, A.A. Snesarev93, S.W. Snow81, J. Snow110, S. Snyder24, R. Sobie168,k, J. Sodomka126, A. Soffer152, C.A. Solans166, M. Solar126, J. Solc126,E.Yu. Soldatov 95, U. Soldevila 166, E. Solfaroli Camillocci 131a,131b, A.A. Solodkov127, O.V. Solovyanov127, V. Solovyev120, N. Soni85, V. Sopko126, B. Sopko126, M. Sosebee 7, R. Soualah163a,163c, A. Soukharev106, S. Spagnolo71a,71b, F. Spanò75, R. Spighi19a, G. Spigo29, R. Spiwoks29, M. Spousta125,ai, T. Spreitzer 157,B. Spurlock7, R.D. St. Denis52, J. Stahlman119, R. Stamen57a, E. Stanecka38, R.W. Stanek5,C. Stanescu 133a, M. Stanescu-Bellu41, S. Stapnes116, E.A. Starchenko127, J. Stark54, P. Staroba124, P. Starovoitov41, R. Staszewski38, A. Staude97, P. Stavina 143a,∗, G. Steele52, P. Steinbach43,P. Steinberg24, I. Stekl126, B. Stelzer141, H.J. Stelzer87, O. Stelzer-Chilton158a, H. Stenzel51, S. Stern98, G.A. Stewart 29, J.A. Stillings 20, M.C. Stockton84, K. Stoerig47, G. Stoicea25a, S. Stonjek98, P. Strachota125, A.R. Stradling 7, A. Straessner43, J. Strandberg146, S. Strandberg145a,145b, A. Strandlie116, M. Strang108,E. Strauss142, M. Strauss110, P. Strizenec143b, R. Ströhmer173, D.M. Strom113, J.A. Strong75,∗, R. Stroynowski39, J. Strube128, B. Stugu13, I. Stumer24,∗, J. Stupak147, P. Sturm174, N.A. Styles41,D.A. Soh150,w, D. Su142, HS. Subramania 2, A. Succurro11, Y. Sugaya 115, C. Suhr 105, M. Suk 125, V.V. Sulin 93, S. Sultansoy 3d, T. Sumida 66, X. Sun 54, J.E. Sundermann 47, K. Suruliz 138, G. Susinno 36a,36b,M.R. Sutton 148, Y. Suzuki 64, Y. Suzuki65, M. Svatos124, S. Swedish167, I. Sykora143a, T. Sykora125, J. Sánchez166, D. Ta104, K. Tackmann41, A. Taffard162, R. Tafirout158a, N. Taiblum152, Y. Takahashi 100,H. Takai 24, R. Takashima67, H. Takeda65, T. Takeshita139, Y. Takubo64, M. Talby82, A. Talyshev106,f,M.C. Tamsett24, K.G. Tan85, J. Tanaka 154, R. Tanaka 114, S. Tanaka 130, S. Tanaka 64, A.J. Tanasijczuk 141,K. Tani 65, N. Tannoury 82, S. Tapprogge80, D. Tardif157, S. Tarem151, F. Tarrade28, G.F. Tartarelli 88a, P. Tas125,M.Tasevsky124, E. Tassi 36a,36b, M. Tatarkhanov 14, Y. Tayalati134d, C. Taylor76, F.E. Taylor 91, G.N. Taylor85, W. Taylor158b, M. Teinturier 114, F.A. Teischinger 29, M. Teixeira Dias Castanheira 74,P. Teixeira-Dias 75, K.K. Temming47, H. Ten Kate29, P.K. Teng150, S. Terada64, K. Terashi154, J. Terron79, M. Testa 46, R.J. Teuscher 157,k, J. Therhaag 20, T. Theveneaux-Pelzer77, S. Thoma47, J.P. Thomas 17,E.N. Thompson 34, P.D. Thompson 17, P.D. Thompson 157, A.S. Thompson 52, L.A. Thomsen 35,E. Thomson 119, M. Thomson 27, W.M. Thong85, R.P. Thun86, F. Tian 34, M.J. Tibbetts14, T. Tic124, V.O. Tikhomirov 93, Y.A. Tikhonov 106,f , S. Timoshenko 95, P. Tipton175, S. Tisserant 82, T. Todorov 4, S. Todorova-Nova 160, B. Toggerson162, J. Tojo68, S. Tokár143a, K. Tokushuku64, K. Tollefson 87, M. Tomoto 100, L. Tompkins30, K. Toms102, A. Tonoyan13, C. Topfel16, N.D. Topilin63, I. Torchiani29,E. Torrence113, H. Torres77, E. Torró Pastor166, J. Toth82,ad, F. Touchard82, D.R. Tovey138, T. Trefzger173,L. Tremblet29, A. Tricoli29, I.M. Trigger 158a, S. Trincaz-Duvoid77, M.F. Tripiana69, N. Triplett24, W. Trischuk 157, B. Trocmé54, C. Troncon88a, M. Trottier-McDonald 141, M. Trzebinski 38, A. Trzupek 38,C. Tsarouchas 29, J.C.-L. Tseng 117, M. Tsiakiris104, P.V. Tsiareshka89, D. Tsionou 4,aj, G. Tsipolitis 9, S. Tsiskaridze 11, V. Tsiskaridze 47, E.G. Tskhadadze 50a, I.I. Tsukerman94, V. Tsulaia14, J.-W. Tsung20, S. Tsuno64, D. Tsybychev147, A. Tua138, A. Tudorache25a, V. Tudorache25a, J.M. Tuggle30, M. Turala38,D. Turecek126, I. Turk Cakir3e, E. Turlay104, R. Turra88a,88b, P.M. Tuts34, A. Tykhonov 73,M. Tylmad 145a,145b, M. Tyndel128, G. Tzanakos8, K. Uchida20, I. Ueda154, R. Ueno28, M. Ugland13, M. Uhlenbrock 20, M. Uhrmacher53, F. Ukegawa159, G. Unal29, A. Undrus24, G. Unel162, Y. Unno 64, D. Urbaniec34, G. Usai7, M. Uslenghi 118a,118b, L. Vacavant82, V. Vacek126, B. Vachon84, S. Vahsen14, J. Valenta 124, S. Valentinetti19a,19b, A. Valero166, S. Valkar125, E. Valladolid Gallego 166, S. Vallecorsa 151, J.A. Valls Ferrer166, R. Van Berg119, P.C. Van Der Deijl104, R. van der Geer 104, H. van der Graaf 104, R. Van Der Leeuw104, E. van der Poel104, D. van der Ster29, N. van Eldik29, P. van Gemmeren 5,

ATLAS Collaboration / Physics Letters B 721 (2013) 32–50 47

I. van Vulpen 104, M. Vanadia 98, W. Vandelli 29, A. Vaniachine 5, P. Vankov41, F. Vannucci 77, R. Vari131a,E.W. Varnes6, T. Varol83, D. Varouchas 14, A. Vartapetian 7, K.E. Varvell 149, V.I. Vassilakopoulos 55,F. Vazeille 33, T. Vazquez Schroeder 53, G. Vegni 88a,88b, J.J. Veillet 114, F. Veloso 123a, R. Veness 29, S. Veneziano 131a, A. Ventura 71a,71b, D. Ventura 83, M. Venturi 47, N. Venturi 157, V. Vercesi 118a, M. Verducci 137, W. Verkerke 104, J.C. Vermeulen 104, A. Vest 43, M.C. Vetterli141,d, I. Vichou 164, T. Vickey 144b,ak, O.E. Vickey Boeriu 144b, G.H.A. Viehhauser 117, S. Viel 167, M. Villa 19a,19b, M. Villaplana Perez 166, E. Vilucchi 46, M.G. Vincter28, E. Vinek29, V.B. Vinogradov 63, M. Virchaux 135,∗,J. Virzi 14, O. Vitells 171, M. Viti 41, I. Vivarelli 47, F. Vives Vaque2, S. Vlachos9, D. Vladoiu97, M. Vlasak126, A. Vogel20, P. Vokac126, T. Volansky152, G. Volpi46, M. Volpi85, G. Volpini88a, H. von der Schmitt98,H. von Radziewski 47, E. von Toerne 20, V. Vorobel 125,V.Vorwerk11,M.Vos166, R. Voss 29, T.T. Voss 174, J.H. Vossebeld 72, N. Vranjes 135, M. Vranjes Milosavljevic104, V. Vrba124, M. Vreeswijk 104, T. Vu Anh47, R. Vuillermet 29, I. Vukotic 30, W. Wagner174, P. Wagner119, H. Wahlen174, S. Wahrmund 43,J. Wakabayashi 100, S. Walch86, J. Walder70, R. Walker97, W. Walkowiak 140, R. Wall175, P. Waller 72, B. Walsh 175, C. Wang44, H. Wang172, H. Wang32b,al, J. Wang150, J. Wang54, R. Wang102, S.M. Wang150, T. Wang 20, A. Warburton84, C.P. Ward27, M. Warsinsky47, A. Washbrook45, C. Wasicki41, I. Watanabe 65, P.M. Watkins 17, A.T. Watson 17, I.J. Watson 149, M.F. Watson 17, G. Watts137, S. Watts81, A.T. Waugh149, B.M. Waugh 76, M.S. Weber 16, P. Weber 53, A.R. Weidberg 117, P. Weigell98, J. Weingarten53, C. Weiser47,H. Wellenstein 22, P.S. Wells 29, T. Wenaus24, D. Wendland15, Z. Weng150,w, T. Wengler 29, S. Wenig29,N. Wermes 20, M. Werner 47, P. Werner 29, M. Werth162, M. Wessels 57a, J. Wetter160, C. Weydert54,K. Whalen 28, S.J. Wheeler-Ellis162, A. White7, M.J. White85, S. White121a,121b, S.R. Whitehead 117, D. Whiteson 162, D. Whittington 59, F. Wicek114, D. Wicke174, F.J. Wickens128, W. Wiedenmann 172, M. Wielers 128, P. Wienemann 20, C. Wiglesworth 74, L.A.M. Wiik-Fuchs47, P.A. Wijeratne76, A. Wildauer 98, M.A. Wildt41,s, I. Wilhelm125, H.G. Wilkens29, J.Z. Will 97, E. Williams 34,H.H. Williams 119, W. Willis 34, S. Willocq 83, J.A. Wilson 17, M.G. Wilson 142, A. Wilson 86,I. Wingerter-Seez 4, S. Winkelmann 47, F. Winklmeier 29, M. Wittgen 142, S.J. Wollstadt80, M.W. Wolter38,H. Wolters 123a,h, W.C. Wong40, G. Wooden 86, B.K. Wosiek 38, J. Wotschack29, M.J. Woudstra81, K.W. Wozniak 38, K. Wraight 52, M. Wright 52, B. Wrona72, S.L. Wu172, X. Wu48, Y. Wu32b,am, E. Wulf34, B.M. Wynne 45, S. Xella 35, M. Xiao 135, S. Xie47, C. Xu32b,z, D. Xu138, B. Yabsley149, S. Yacoob 144a,an, M. Yamada 64, H. Yamaguchi 154, A. Yamamoto 64, K. Yamamoto 62, S. Yamamoto 154, T. Yamamura 154, T. Yamanaka 154, J. Yamaoka 44, T. Yamazaki 154, Y. Yamazaki 65, Z. Yan21, H. Yang86, U.K. Yang81, Y. Yang 59, Z. Yang145a,145b, S. Yanush90, L. Yao32a, Y. Yao14, Y. Yasu64, G.V. Ybeles Smit129, J. Ye39, S. Ye 24, M. Yilmaz 3c, R. Yoosoofmiya 122, K. Yorita 170, R. Yoshida 5, C. Young142, C.J. Young117, S. Youssef 21, D. Yu24, J. Yu7, J. Yu111, L. Yuan65, A. Yurkewicz 105, B. Zabinski 38, R. Zaidan61,A.M. Zaitsev 127, Z. Zajacova29, L. Zanello131a,131b, D. Zanzi98, A. Zaytsev24, C. Zeitnitz174, M. Zeman124, A. Zemla 38, C. Zendler20, O. Zenin127, T. Ženiš143a, Z. Zinonos 121a,121b, S. Zenz14, D. Zerwas114,G. Zevi della Porta 56, Z. Zhan32d, D. Zhang 32b,al, H. Zhang 87, J. Zhang 5, X. Zhang 32d, Z. Zhang 114,L. Zhao 107, T. Zhao137, Z. Zhao32b, A. Zhemchugov 63, J. Zhong117, B. Zhou 86, N. Zhou162, Y. Zhou150,C.G. Zhu 32d, H. Zhu41, J. Zhu86, Y. Zhu32b, X. Zhuang97, V. Zhuravlov98, D. Zieminska59, N.I. Zimin 63, R. Zimmermann 20, S. Zimmermann 20, S. Zimmermann 47, M. Ziolkowski 140, R. Zitoun4, L. Živkovic´ 34, V.V. Zmouchko 127,∗, G. Zobernig 172, A. Zoccoli 19a,19b, M. zur Nedden15, V. Zutshi105, L. Zwalinski291 Physics Department, SUNY Albany, Albany, NY, United States2 Department of Physics, University of Alberta, Edmonton, AB, Canada3 (a) Department of Physics, Ankara University, Ankara; (b) Department of Physics, Dumlupinar University, Kutahya; (c) Department of Physics, Gazi University, Ankara; (d) Division of Physics, TOBB University of Economics and Technology, Ankara; (e) Turkish Atomic Energy Authority, Ankara, Turkey4 LAPP, CNRS/IN2P3 and Université de Savoie, Annecy-le-Vieux, France5 High Energy Physics Division, Argonne National Laboratory, Argonne, IL, United States6 Department of Physics, University of Arizona, Tucson, AZ, United States7 Department of Physics, The University of Texas at Arlington, Arlington, TX, United States8 Physics Department, University of Athens, Athens, Greece9 Physics Department, National Technical University of Athens, Zografou, Greece10 Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan11 Institut de Física d'Altes Energies and Departament de Física de la Universitat Autònoma de Barcelona and ICREA, Barcelona, Spain12 (a) Institute of Physics, University of Belgrade, Belgrade; (b) Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia13 Department for Physics and Technology, University of Bergen, Bergen, Norway14 Physics Division, Lawrence Berkeley National Laboratory and University of California, Berkeley, CA, United States15 Department of Physics, Humboldt University, Berlin, Germany16 Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland17 School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom

48 ATLAS Collaboration / Physics Letters B 721 (2013) 32-50

18 (a) Department ofPhysics, Bogazici University, Istanbul; (b) Division ofPhysics, Dogus University, Istanbul; (c) Department ofPhysics Engineering, Gaziantep University, Gaziantep;(d) Department ofPhysics, Istanbul Technical University, Istanbul, Turkey19 (a) INFN Sezione di Bologna; (b) Dipartimento di Fisica, Università di Bologna, Bologna, Italy20 Physikalisches Institut, University ofBonn, Bonn, Germany21 Department ofPhysics, Boston University, Boston, MA, United States22 Department ofPhysics, Brandeis University, Waltham, MA, United States23 (a) Universidade Federaldo Rio DeJaneiro COPPE/EE/IF, Rio deJaneiro; (b) Federal University ofJuiz de Fora (UFJF), JuizdeFora; (c) Federal University ofSao Joao del Rei (UFSJ), Sao Joao del Rei; (d) Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, Brazil24 Physics Department, Brookhaven National Laboratory, Upton, NY, United States25 (a) National Institute ofPhysics and NuclearEngineering, Bucharest; (b) University Politehnica Bucharest, Bucharest; (c) West University in Timisoara, Timisoara, Romania26 Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina27 Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom28 Department ofPhysics, Carleton University, Ottawa, ON, Canada29 CERN, Geneva, Switzerland30 Enrico Fermi Institute, University ofChicago, Chicago, IL, United States31 (a) Departamento de Física, Pontificia Universidad Católica de Chile, Santiago; (b) Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile32 (a) Institute ofHigh Energy Physics, Chinese Academy ofSciences, Beijing; (b) Department ofModern Physics, University ofScience and Technology ofChina, Anhui; (c) Department of Physics, Nanjing University, Jiangsu; (d) School ofPhysics, Shandong University, Shandong, China33 Laboratoire de Physique Corpusculaire, Clermont Université and Université Blaise Pascal and CNRS/IN2P3, Clermont-Ferrand, France34 Nevis Laboratory, Columbia University, Irvington, NY, United States35 Niels Bohr Institute, University ofCopenhagen, Kobenhavn, Denmark36 (a) INFN Gruppo Collegato di Cosenza; (b) Dipartimento di Fisica, Università della Calabria, Rende, Italy37 AGH University ofScienceandTechnology, Faculty ofPhysics and AppliedComputerScience, Krakow, Poland38 The Henryk Niewodniczanski Institute ofNuclear Physics, Polish Academy ofSciences, Krakow, Poland39 Physics Department, Southern Methodist University, Dallas, TX, United States40 Physics Department, University ofTexas at Dallas, Richardson, TX, United States41 DESY, Hamburgand Zeuthen, Germany42 Institut für Experimentelle Physik IV,